diff --git a/MEs-Roadmap-Documentation.md b/MEs-Roadmap-Documentation.md
index 7e5aa1b069e..97e61e0513a 100644
--- a/MEs-Roadmap-Documentation.md
+++ b/MEs-Roadmap-Documentation.md
@@ -1,14 +1,14 @@
 # 📝 Most immediate things to-do list
 
 - ### High priority
-    - 🐛 Intimidate and other ETB abilities proc twice at the start of wild MEs (fight or flight, dark deal) 
-    - ⚙️ Add a tag system so MEs don't show where they shouldn't and bricking Challenge runs:
+    - ⚙️ Add a tag system so MEs to filter or change spawn rates in Challenge runs:
       - noChallenge (cant be spawned in challenge runs)
       - allChallenge (can spawn in all challenge modes)
       - (typespecific)Challenge: 
         - Example: fireOnly (can only spawn in fire related challenges)
 
 - ### Medium priority
+    - ⚙️ Update Chest visuals for Mysterious Chest (with animated chest)
 
 - ### Low priority
     - 🐛 Mysterious Challengers can spawn two trainers (or three) of the same type [Dev comment: not a bug]
@@ -106,9 +106,9 @@ Events (referred to as 'Mysterious Encounters, MEs' in the code) aim to be an ad
   
   ### 🌟 **Rarity** tier of the ME, common by default.
     - ⚪ Common pool 
-    - 🔵 Rare pool 
-    - 🟣 Epic pool
-    - 🟡 Legendary pool
+    - 🔵 Uncommon pool 
+    - 🟣 Rare pool
+    - 🟡 Super Rare pool
 
   ### **Optional Requirements** for Mystery Encounters.
   - 🛠️ They give granular control over whether encounters will spawn in certain situations
@@ -135,13 +135,10 @@ Events (referred to as 'Mysterious Encounters, MEs' in the code) aim to be an ad
 
 # 📝 Known bugs (squash 'em all!):
   - ## 🔴 __**Really bad ones**__
-    - 🐛 Picking up certain items in Fight or Flight is still broken. Workaround is leave encounter.
-    - 🐛 Modifiers that are applied to pokemon get skipped in Fight or Flight.
 
   - ## 🟡 __**Bad ones under certain circumstances**__
     - 🐛 Needs further replication : At wave 51, wild PKMN encounter caused a freezed after pressing "ESC" key upon being asked to switch PKMNs
     - 🐛 Wave seed generates different encounter data if you roll to a new wave, see the spawned stuff, and refresh the app
-    - 🐛 Type-buffing items (like Silk Scarf) get swapped around when offered as a reward in Fight or Flight
 
   - ## 🟢 __**Non-game breaking**__
     - Both of these bugs seem to have in common that they don't "forget" their last passed string:
@@ -157,7 +154,6 @@ Events (referred to as 'Mysterious Encounters, MEs' in the code) aim to be an ad
 #### More requirements (with helper functions)
 - Having X item
 - Having Y amount of X item
-- Being in a specific Biome
 - A Pokémon X in player's party can learn Y move
 - A Pokémon X in player's party knows Y move
 - A Pokémon X in player's party has Y ability
diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index 0515800e53f..fe3023cbc22 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -93,7 +93,7 @@ import { UiTheme } from "#enums/ui-theme";
 import { TimedEventManager } from "#app/timed-event-manager.js";
 import i18next from "i18next";
 import MysteryEncounter, { MysteryEncounterTier, MysteryEncounterVariant } from "./data/mystery-encounter";
-import { mysteryEncountersByBiome, allMysteryEncounters, BASE_MYSTERY_ENCOUNTER_WEIGHT, AVERAGE_ENCOUNTERS_PER_RUN_TARGET } from "./data/mystery-encounters/mystery-encounters";
+import { mysteryEncountersByBiome, allMysteryEncounters, BASE_MYSTERY_ENCOUNTER_WEIGHT, AVERAGE_ENCOUNTERS_PER_RUN_TARGET, WIGHT_INCREMENT_ON_SPAWN_MISS } from "./data/mystery-encounters/mystery-encounters";
 import { MysteryEncounterFlags } from "#app/data/mystery-encounter-flags";
 import { MysteryEncounterType } from "#enums/mystery-encounter-type";
 
@@ -1098,22 +1098,22 @@ export default class BattleScene extends SceneBase {
 
       // Check for mystery encounter
       // Can only occur in place of a standard wild battle, waves 10-180
-      // let testStartingWeight = 10;
-      // while (testStartingWeight < 30) {
+      // let testStartingWeight = 0;
+      // while (testStartingWeight < 20) {
       //   calculateMEAggregateStats(this, testStartingWeight);
-      //   testStartingWeight += 2;
+      //   testStartingWeight += 1;
       // }
       if (this.gameMode.hasMysteryEncounters && newBattleType === BattleType.WILD && !this.gameMode.isBoss(newWaveIndex) && newWaveIndex < 180 && newWaveIndex > 10) {
         const roll = Utils.randSeedInt(256);
 
-        // Base spawn weight is 3/256, and increases by 1/256 for each missed attempt at spawning an encounter on a valid floor
-        const sessionEncounterRate = !isNullOrUndefined(this.mysteryEncounterFlags?.encounterSpawnChance) ? this.mysteryEncounterFlags.encounterSpawnChance : BASE_MYSTERY_ENCOUNTER_WEIGHT;
+        // Base spawn weight is 1/256, and increases by 5/256 for each missed attempt at spawning an encounter on a valid floor
+        const sessionEncounterRate = !isNullOrUndefined(this.mysteryEncounterData?.encounterSpawnChance) ? this.mysteryEncounterData.encounterSpawnChance : BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT;
 
         // If total number of encounters is lower than expected for the run, slightly favor a new encounter spawn
         // Do the reverse as well
         // Reduces occurrence of runs with very few (<6) and a ton (>10) of encounters
         const expectedEncountersByFloor = AVERAGE_ENCOUNTERS_PER_RUN_TARGET / (180 - 10) * newWaveIndex;
-        const currentRunDiffFromAvg = expectedEncountersByFloor - (this.mysteryEncounterFlags?.encounteredEvents?.length || 0);
+        const currentRunDiffFromAvg = expectedEncountersByFloor - (this.mysteryEncounterData?.encounteredEvents?.length || 0);
         const favoredEncounterRate = sessionEncounterRate + currentRunDiffFromAvg * 5;
 
         const successRate = isNullOrUndefined(Overrides.MYSTERY_ENCOUNTER_RATE_OVERRIDE) ? favoredEncounterRate : Overrides.MYSTERY_ENCOUNTER_RATE_OVERRIDE;
@@ -1121,9 +1121,9 @@ export default class BattleScene extends SceneBase {
         if (roll < successRate) {
           newBattleType = BattleType.MYSTERY_ENCOUNTER;
           // Reset base spawn weight
-          this.mysteryEncounterFlags.encounterSpawnChance = BASE_MYSTERY_ENCOUNTER_WEIGHT;
+          this.mysteryEncounterData.encounterSpawnChance = BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT;
         } else {
-          this.mysteryEncounterFlags.encounterSpawnChance = sessionEncounterRate + 1;
+          this.mysteryEncounterData.encounterSpawnChance = sessionEncounterRate + WIGHT_INCREMENT_ON_SPAWN_MISS;
         }
       }
     }
@@ -1168,7 +1168,9 @@ export default class BattleScene extends SceneBase {
     if (newBattleType === BattleType.MYSTERY_ENCOUNTER) {
       // Disable double battle on mystery encounters (it may be re-enabled as part of encounter)
       this.currentBattle.double = false;
-      this.currentBattle.mysteryEncounter = this.getMysteryEncounter(mysteryEncounter);
+      this.executeWithSeedOffset(() => {
+        this.currentBattle.mysteryEncounter = this.getMysteryEncounter(mysteryEncounter);
+      }, this.currentBattle.waveIndex << 4);
     }
 
     //this.pushPhase(new TrainerMessageTestPhase(this, TrainerType.RIVAL, TrainerType.RIVAL_2, TrainerType.RIVAL_3, TrainerType.RIVAL_4, TrainerType.RIVAL_5, TrainerType.RIVAL_6));
@@ -2652,10 +2654,10 @@ export default class BattleScene extends SceneBase {
     }
 
     // Check for queued encounters first
-    if (!encounter && this.mysteryEncounterFlags?.nextEncounterQueue?.length > 0) {
+    if (!encounter && this.mysteryEncounterData?.nextEncounterQueue?.length > 0) {
       let i = 0;
-      while (i < this.mysteryEncounterFlags.nextEncounterQueue.length && !!encounter) {
-        const candidate = this.mysteryEncounterFlags.nextEncounterQueue[i];
+      while (i < this.mysteryEncounterData.nextEncounterQueue.length && !!encounter) {
+        const candidate = this.mysteryEncounterData.nextEncounterQueue[i];
         const forcedChance = candidate[1];
         if (Utils.randSeedInt(100) < forcedChance) {
           encounter = allMysteryEncounters[candidate[0]];
@@ -2675,7 +2677,7 @@ export default class BattleScene extends SceneBase {
     const tierWeights = [61, 40, 21, 6];
 
     // Adjust tier weights by previously encountered events to lower odds of only common/uncommons in run
-    this.mysteryEncounterFlags.encounteredEvents.forEach(val => {
+    this.mysteryEncounterData.encounteredEvents.forEach(val => {
       const tier = val[1];
       if (tier === MysteryEncounterTier.COMMON) {
         tierWeights[0] = tierWeights[0] - 6;
@@ -2697,7 +2699,7 @@ export default class BattleScene extends SceneBase {
 
     let availableEncounters = [];
     // New encounter will never be the same as the most recent encounter
-    const previousEncounter = this.mysteryEncounterFlags.encounteredEvents?.length > 0 ? this.mysteryEncounterFlags.encounteredEvents[this.mysteryEncounterFlags.encounteredEvents.length - 1][0] : null;
+    const previousEncounter = this.mysteryEncounterData.encounteredEvents?.length > 0 ? this.mysteryEncounterData.encounteredEvents[this.mysteryEncounterData.encounteredEvents.length - 1][0] : null;
     const biomeMysteryEncounters = mysteryEncountersByBiome.get(this.arena.biomeType);
     // If no valid encounters exist at tier, checks next tier down, continuing until there are some encounters available
     while (availableEncounters.length === 0 && tier >= 0) {
diff --git a/src/data/mystery-encounter-flags.ts b/src/data/mystery-encounter-data.ts
similarity index 61%
rename from src/data/mystery-encounter-flags.ts
rename to src/data/mystery-encounter-data.ts
index 33ef84e2d1d..922bc30cbc3 100644
--- a/src/data/mystery-encounter-flags.ts
+++ b/src/data/mystery-encounter-data.ts
@@ -1,14 +1,14 @@
 import {MysteryEncounterTier} from "#app/data/mystery-encounter";
 import {MysteryEncounterType} from "#enums/mystery-encounter-type";
-import {BASE_MYSTERY_ENCOUNTER_WEIGHT} from "#app/data/mystery-encounters/mystery-encounters";
+import {BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT} from "#app/data/mystery-encounters/mystery-encounters";
 import {isNullOrUndefined} from "../utils";
 
-export class MysteryEncounterFlags {
+export class MysteryEncounterData {
   encounteredEvents: [MysteryEncounterType, MysteryEncounterTier][] = [];
-  encounterSpawnChance: number = BASE_MYSTERY_ENCOUNTER_WEIGHT;
+  encounterSpawnChance: number = BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT;
   nextEncounterQueue: [MysteryEncounterType, integer][] = [];
 
-  constructor(flags: MysteryEncounterFlags) {
+  constructor(flags: MysteryEncounterData) {
     if (!isNullOrUndefined(flags)) {
       Object.assign(this, flags);
     }
diff --git a/src/data/mystery-encounter-requirements.ts b/src/data/mystery-encounter-requirements.ts
index d88ec530a74..1a105f2f83b 100644
--- a/src/data/mystery-encounter-requirements.ts
+++ b/src/data/mystery-encounter-requirements.ts
@@ -63,11 +63,11 @@ export class PreviousEncounterRequirement extends EncounterSceneRequirement {
   }
 
   meetsRequirement(scene: BattleScene): boolean {
-    return scene.mysteryEncounterFlags.encounteredEvents.some(e => e[0] === this.previousEncounterRequirement);
+    return scene.mysteryEncounterData.encounteredEvents.some(e => e[0] === this.previousEncounterRequirement);
   }
 
   getDialogueToken(scene: BattleScene, pokemon?: PlayerPokemon): [string, string] {
-    return ["previousEncounter", scene.mysteryEncounterFlags.encounteredEvents.find(e => e[0] === this.previousEncounterRequirement)[0].toString()];
+    return ["previousEncounter", scene.mysteryEncounterData.encounteredEvents.find(e => e[0] === this.previousEncounterRequirement)[0].toString()];
   }
 }
 
diff --git a/src/data/mystery-encounters/mystery-encounter-utils.ts b/src/data/mystery-encounters/mystery-encounter-utils.ts
index 2a69becf1ef..8cd4963daa1 100644
--- a/src/data/mystery-encounters/mystery-encounter-utils.ts
+++ b/src/data/mystery-encounters/mystery-encounter-utils.ts
@@ -27,10 +27,10 @@ import {BattlerTagType} from "#enums/battler-tag-type";
 import PokemonData from "#app/system/pokemon-data";
 import {Biome} from "#enums/biome";
 import {biomeLinks} from "#app/data/biomes";
-import {EncounterSceneRequirement} from "#app/data/mystery-encounter-requirements";
 import {Mode} from "#app/ui/ui";
 import {PartyOption, PartyUiMode} from "#app/ui/party-ui-handler";
 import {OptionSelectConfig, OptionSelectItem} from "#app/ui/abstact-option-select-ui-handler";
+import {WIGHT_INCREMENT_ON_SPAWN_MISS} from "#app/data/mystery-encounters/mystery-encounters";
 
 /**
  *
@@ -62,15 +62,15 @@ export function getRandomPlayerPokemon(scene: BattleScene, isAllowedInBattle: bo
   return chosenPokemon;
 }
 
-export function getTokensFromScene(scene: BattleScene, reqs: EncounterSceneRequirement[]): Array<[RegExp, String]> {
-  const arr = [];
-  if (scene) {
-    for (const req of reqs) {
-      req.getDialogueToken(scene);
-    }
-  }
-  return arr;
-}
+// export function getTokensFromScene(scene: BattleScene, reqs: EncounterSceneRequirement[]): Array<[RegExp, String]> {
+//   const arr = [];
+//   if (scene) {
+//     for (const req of reqs) {
+//       req.getDialogueToken(scene);
+//     }
+//   }
+//   return arr;
+// }
 
 /**
  * Ties are broken by whatever mon is closer to the front of the party
@@ -114,6 +114,48 @@ export function getLowestLevelPlayerPokemon(scene: BattleScene, unfainted: boole
   return pokemon;
 }
 
+/**
+ *
+ * NOTE: This returns ANY random species, including those locked behind eggs, etc.
+ * @param starterTiers
+ * @param excludedSpecies
+ * @param types
+ * @returns
+ */
+export function getRandomSpeciesByStarterTier(starterTiers: number | [number, number], excludedSpecies?: Species[], types?: Type[]): Species {
+  let min = starterTiers instanceof Array ? starterTiers[0] : starterTiers;
+  let max = starterTiers instanceof Array ? starterTiers[1] : starterTiers;
+
+  let filteredSpecies: [PokemonSpecies, number][] = Object.keys(speciesStarters)
+    .map(s => [parseInt(s) as Species, speciesStarters[s] as number])
+    .filter(s => getPokemonSpecies(s[0]) && (!excludedSpecies || !excludedSpecies.includes(s[0])))
+    .map(s => [getPokemonSpecies(s[0]), s[1]]);
+
+  if (!isNullOrUndefined(types) && types.length > 0) {
+    filteredSpecies = filteredSpecies.filter(s => types.includes(s[0].type1) || types.includes(s[0].type2));
+  }
+
+  // If no filtered mons exist at specified starter tiers, will expand starter search range until there are
+  // Starts by decrementing starter tier min until it is 0, then increments tier max up to 10
+  let tryFilterStarterTiers: [PokemonSpecies, number][] = filteredSpecies.filter(s => (s[1] >= min && s[1] <= max));
+  while (tryFilterStarterTiers.length === 0 && (min !== 0 && max !== 10)) {
+    if (min > 0) {
+      min--;
+    } else {
+      max++;
+    }
+
+    tryFilterStarterTiers = filteredSpecies.filter(s => s[1] >= min && s[1] <= max);
+  }
+
+  if (tryFilterStarterTiers.length > 0) {
+    const index = Utils.randSeedInt(tryFilterStarterTiers.length);
+    return Phaser.Math.RND.shuffle(tryFilterStarterTiers)[index][0].speciesId;
+  }
+
+  return Species.BULBASAUR;
+}
+
 export function koPlayerPokemon(pokemon: PlayerPokemon) {
   pokemon.hp = 0;
   pokemon.trySetStatus(StatusEffect.FAINT);
@@ -173,48 +215,6 @@ export function showEncounterDialogue(scene: BattleScene, textContentKey: Templa
   scene.ui.showDialogue(text, speaker, null, callback, 0, 0);
 }
 
-/**
- *
- * NOTE: This returns ANY random species, including those locked behind eggs, etc.
- * @param starterTiers
- * @param excludedSpecies
- * @param types
- * @returns
- */
-export function getRandomSpeciesByStarterTier(starterTiers: number | [number, number], excludedSpecies?: Species[], types?: Type[]): Species {
-  let min = starterTiers instanceof Array ? starterTiers[0] : starterTiers;
-  let max = starterTiers instanceof Array ? starterTiers[1] : starterTiers;
-
-  let filteredSpecies: [PokemonSpecies, number][] = Object.keys(speciesStarters)
-    .map(s => [parseInt(s) as Species, speciesStarters[s] as number])
-    .filter(s => getPokemonSpecies(s[0]) && !excludedSpecies.includes(s[0]))
-    .map(s => [getPokemonSpecies(s[0]), s[1]]);
-
-  if (!isNullOrUndefined(types) && types.length > 0) {
-    filteredSpecies = filteredSpecies.filter(s => types.includes(s[0].type1) || types.includes(s[0].type2));
-  }
-
-  // If no filtered mons exist at specified starter tiers, will expand starter search range until there are
-  // Starts by decrementing starter tier min until it is 0, then increments tier max up to 10
-  let tryFilterStarterTiers: [PokemonSpecies, number][] = filteredSpecies.filter(s => (s[1] >= min && s[1] <= max));
-  while (tryFilterStarterTiers.length === 0 && (min !== 0 && max !== 10)) {
-    if (min > 0) {
-      min--;
-    } else {
-      max++;
-    }
-
-    tryFilterStarterTiers = filteredSpecies.filter(s => s[1] >= min && s[1] <= max);
-  }
-
-  if (tryFilterStarterTiers.length > 0) {
-    const index = Utils.randSeedInt(tryFilterStarterTiers.length);
-    return Phaser.Math.RND.shuffle(tryFilterStarterTiers)[index][0].speciesId;
-  }
-
-  return Species.BULBASAUR;
-}
-
 export class EnemyPokemonConfig {
   species: PokemonSpecies;
   isBoss: boolean = false;
@@ -594,10 +594,10 @@ export function handleMysteryEncounterVictory(scene: BattleScene, addHealPhase:
 export function calculateMEAggregateStats(scene: BattleScene, baseSpawnWeight: number) {
   const numRuns = 1000;
   let run = 0;
-  const targetEncountersPerRun = 15;
+  const targetEncountersPerRun = 15; // AVERAGE_ENCOUNTERS_PER_RUN_TARGET
 
   const calculateNumEncounters = (): number[] => {
-    let encounterRate = baseSpawnWeight;
+    let encounterRate = baseSpawnWeight; // BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT
     const numEncounters = [0, 0, 0, 0];
     let currentBiome = Biome.TOWN;
     let currentArena = scene.newArena(currentBiome);
@@ -669,7 +669,7 @@ export function calculateMEAggregateStats(scene: BattleScene, baseSpawnWeight: n
 
         tierValue > commonThreshold ? ++numEncounters[0] : tierValue > uncommonThreshold ? ++numEncounters[1] : tierValue > rareThreshold ? ++numEncounters[2] : ++numEncounters[3];
       } else {
-        encounterRate++;
+        encounterRate += WIGHT_INCREMENT_ON_SPAWN_MISS;
       }
     }
 
diff --git a/src/data/mystery-encounters/mystery-encounters.ts b/src/data/mystery-encounters/mystery-encounters.ts
index 1a0f6f2a1ce..918868d3d2c 100644
--- a/src/data/mystery-encounters/mystery-encounters.ts
+++ b/src/data/mystery-encounters/mystery-encounters.ts
@@ -8,7 +8,9 @@ import { Biome } from "#app/enums/biome";
 import { SleepingSnorlaxEncounter } from "./sleeping-snorlax";
 import { MysteryEncounterType } from "#enums/mystery-encounter-type";
 
-export const BASE_MYSTERY_ENCOUNTER_WEIGHT = 19;
+// Spawn chance: (BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT + WIGHT_INCREMENT_ON_SPAWN_MISS * <number of missed spawns>) / 256
+export const BASE_MYSTERY_ENCOUNTER_SPAWN_WEIGHT = 1;
+export const WIGHT_INCREMENT_ON_SPAWN_MISS = 5;
 export const AVERAGE_ENCOUNTERS_PER_RUN_TARGET = 15;
 
 export const allMysteryEncounters : {[encounterType:string]: MysteryEncounter} = {};
diff --git a/src/locales/en/mystery-encounter.ts b/src/locales/en/mystery-encounter.ts
index b928fa38f54..f6b3a80e0ec 100644
--- a/src/locales/en/mystery-encounter.ts
+++ b/src/locales/en/mystery-encounter.ts
@@ -1,6 +1,8 @@
 import {SimpleTranslationEntries} from "#app/interfaces/locales";
 
 export const mysteryEncounter: SimpleTranslationEntries = {
+  // DO NOT REMOVE
+  "unit_test_dialogue": "@ec{test}@ec{test} @ec{test@ec{test}} @ec{test1} @ec{test\} @ec{test\\} @ec{test\\\} {test}",
 
   // Mysterious Encounters -- Common Tier
 
diff --git a/src/phases.ts b/src/phases.ts
index ffd9c0b609a..6bbc5f2d6d6 100644
--- a/src/phases.ts
+++ b/src/phases.ts
@@ -817,7 +817,7 @@ export class EncounterPhase extends BattlePhase {
         if (mysteryEncounter.onInit) {
           mysteryEncounter.onInit(this.scene);
         }
-        mysteryEncounter.populateDialogueTokensFromRequirements();
+        mysteryEncounter.populateDialogueTokensFromRequirements(this.scene);
       }, this.scene.currentBattle.waveIndex);
 
       // Add intro visuals for mystery encounter
diff --git a/src/phases/mystery-encounter-phase.ts b/src/phases/mystery-encounter-phase.ts
index 2700ec32ae1..1cd04339b84 100644
--- a/src/phases/mystery-encounter-phase.ts
+++ b/src/phases/mystery-encounter-phase.ts
@@ -40,7 +40,7 @@ export class MysteryEncounterPhase extends Phase {
 
     // Sets flag that ME was encountered
     // Can be used in later MEs to check for requirements to spawn, etc.
-    this.scene.mysteryEncounterFlags.encounteredEvents.push([this.scene.currentBattle.mysteryEncounter.encounterType, this.scene.currentBattle.mysteryEncounter.encounterTier]);
+    this.scene.mysteryEncounterData.encounteredEvents.push([this.scene.currentBattle.mysteryEncounter.encounterType, this.scene.currentBattle.mysteryEncounter.encounterTier]);
 
     // Initiates encounter dialogue window and option select
     this.scene.ui.setMode(Mode.MYSTERY_ENCOUNTER);
@@ -55,7 +55,7 @@ export class MysteryEncounterPhase extends Phase {
     }
 
     // Populate dialogue tokens for option requirements
-    this.scene.currentBattle.mysteryEncounter.populateDialogueTokensFromRequirements();
+    this.scene.currentBattle.mysteryEncounter.populateDialogueTokensFromRequirements(this.scene);
 
     if (option.onPreOptionPhase) {
       this.scene.executeWithSeedOffset(async () => {
diff --git a/src/system/game-data.ts b/src/system/game-data.ts
index 14e80623060..07ecfc74f0a 100644
--- a/src/system/game-data.ts
+++ b/src/system/game-data.ts
@@ -40,7 +40,7 @@ import { GameDataType } from "#enums/game-data-type";
 import { Moves } from "#enums/moves";
 import { PlayerGender } from "#enums/player-gender";
 import { Species } from "#enums/species";
-import { MysteryEncounterFlags } from "../data/mystery-encounter-flags";
+import { MysteryEncounterData } from "../data/mystery-encounter-data";
 import MysteryEncounter from "../data/mystery-encounter";
 
 export const defaultStarterSpecies: Species[] = [
@@ -125,7 +125,7 @@ export interface SessionSaveData {
   timestamp: integer;
   challenges: ChallengeData[];
   mysteryEncounter: MysteryEncounter;
-  mysteryEncounterFlags: MysteryEncounterFlags;
+  mysteryEncounterFlags: MysteryEncounterData;
 }
 
 interface Unlocks {
@@ -842,7 +842,7 @@ export class GameData {
       timestamp: new Date().getTime(),
       challenges: scene.gameMode.challenges.map(c => new ChallengeData(c)),
       mysteryEncounter: scene.currentBattle.mysteryEncounter,
-      mysteryEncounterFlags: scene.mysteryEncounterFlags
+      mysteryEncounterFlags: scene.mysteryEncounterData
     } as SessionSaveData;
   }
 
@@ -933,7 +933,7 @@ export class GameData {
           scene.score = sessionData.score;
           scene.updateScoreText();
 
-          scene.mysteryEncounterFlags = sessionData?.mysteryEncounterFlags ? sessionData?.mysteryEncounterFlags : new MysteryEncounterFlags(null);
+          scene.mysteryEncounterData = sessionData?.mysteryEncounterFlags ? sessionData?.mysteryEncounterFlags : new MysteryEncounterData(null);
 
           scene.newArena(sessionData.arena.biome);
 
@@ -1159,7 +1159,7 @@ export class GameData {
       }
 
       if (k === "mysteryEncounterFlags") {
-        return new MysteryEncounterFlags(v);
+        return new MysteryEncounterData(v);
       }
 
       return v;
diff --git a/src/test/mystery-encounter/mystery-encounter-utils.test.ts b/src/test/mystery-encounter/mystery-encounter-utils.test.ts
new file mode 100644
index 00000000000..4b514b13e01
--- /dev/null
+++ b/src/test/mystery-encounter/mystery-encounter-utils.test.ts
@@ -0,0 +1,366 @@
+import {afterEach, beforeAll, beforeEach, describe, expect, it, vi} from "vitest";
+import GameManager from "#app/test/utils/gameManager";
+import Phaser from "phaser";
+import {
+  getHighestLevelPlayerPokemon, getLowestLevelPlayerPokemon,
+  getRandomPlayerPokemon, getRandomSpeciesByStarterTier, getTextWithEncounterDialogueTokens,
+  koPlayerPokemon, queueEncounterMessage, showEncounterDialogue, showEncounterText,
+} from "#app/data/mystery-encounters/mystery-encounter-utils";
+import {initSceneWithoutEncounterPhase} from "#test/utils/gameManagerUtils";
+import {Species} from "#enums/species";
+import BattleScene from "#app/battle-scene";
+import {StatusEffect} from "#app/data/status-effect";
+import MysteryEncounter from "#app/data/mystery-encounter";
+import {MessagePhase} from "#app/phases";
+import {getPokemonSpecies, speciesStarters} from "#app/data/pokemon-species";
+import {Type} from "#app/data/type";
+
+describe("Mystery Encounter Utils", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+  let scene: BattleScene;
+
+  beforeAll(() => {
+    phaserGame = new Phaser.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+    scene = game.scene;
+    initSceneWithoutEncounterPhase(game.scene, [Species.ARCEUS, Species.MANAPHY]);
+    // vi.spyOn(overrides, "MYSTERY_ENCOUNTER_RATE_OVERRIDE", "get").mockReturnValue(256);
+    // vi.spyOn(overrides, "STARTING_WAVE_OVERRIDE", "get").mockReturnValue(11);
+  });
+
+  describe("getRandomPlayerPokemon", () => {
+    it("gets a random pokemon from player party", () => {
+      // Seeds are calculated to return index 0 first, 1 second (if both pokemon are legal)
+      scene.waveSeed = "random";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      let result = getRandomPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+
+      scene.waveSeed = "random2";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      result = getRandomPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+
+    it("gets a fainted pokemon from player party if isAllowedInBattle is false", () => {
+      // Both pokemon fainted
+      scene.getParty().forEach(p => {
+        p.hp = 0;
+        p.trySetStatus(StatusEffect.FAINT);
+        p.updateInfo();
+      });
+
+      // Seeds are calculated to return index 0 first, 1 second (if both pokemon are legal)
+      scene.waveSeed = "random";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      let result = getRandomPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+
+      scene.waveSeed = "random2";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      result = getRandomPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+
+    it("gets an unfainted pokemon from player party if isAllowedInBattle is true", () => {
+      // Only faint 1st pokemon
+      const party = scene.getParty();
+      party[0].hp = 0;
+      party[0].trySetStatus(StatusEffect.FAINT);
+      party[0].updateInfo();
+
+      // Seeds are calculated to return index 0 first, 1 second (if both pokemon are legal)
+      scene.waveSeed = "random";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      let result = getRandomPlayerPokemon(scene, true);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+
+      scene.waveSeed = "random2";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      result = getRandomPlayerPokemon(scene, true);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+    });
+
+    it("returns last unfainted pokemon if doNotReturnLastAbleMon is false", () => {
+      // Only faint 1st pokemon
+      const party = scene.getParty();
+      party[0].hp = 0;
+      party[0].trySetStatus(StatusEffect.FAINT);
+      party[0].updateInfo();
+
+      // Seeds are calculated to return index 0 first, 1 second (if both pokemon are legal)
+      scene.waveSeed = "random";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      let result = getRandomPlayerPokemon(scene, true, false);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+
+      scene.waveSeed = "random2";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      result = getRandomPlayerPokemon(scene, true, false);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+    });
+
+    it("never returns last unfainted pokemon if doNotReturnLastAbleMon is true", () => {
+      // Only faint 1st pokemon
+      const party = scene.getParty();
+      party[0].hp = 0;
+      party[0].trySetStatus(StatusEffect.FAINT);
+      party[0].updateInfo();
+
+      // Seeds are calculated to return index 0 first, 1 second (if both pokemon are legal)
+      scene.waveSeed = "random";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      let result = getRandomPlayerPokemon(scene, true, true);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+
+      scene.waveSeed = "random2";
+      Phaser.Math.RND.sow([ scene.waveSeed ]);
+      scene.rngCounter = 0;
+
+      result = getRandomPlayerPokemon(scene, true, true);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+  });
+
+  describe("getHighestLevelPlayerPokemon", () => {
+    it("gets highest level pokemon", () => {
+      const party = scene.getParty();
+      party[0].level = 100;
+
+      const result = getHighestLevelPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+
+    it("gets highest level pokemon at different index", () => {
+      const party = scene.getParty();
+      party[1].level = 100;
+
+      const result = getHighestLevelPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+    });
+
+    it("breaks ties by getting returning lower index", () => {
+      const party = scene.getParty();
+      party[0].level = 100;
+      party[1].level = 100;
+
+      const result = getHighestLevelPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+
+    it("returns highest level unfainted if unfainted is true", () => {
+      const party = scene.getParty();
+      party[0].level = 100;
+      party[0].hp = 0;
+      party[0].trySetStatus(StatusEffect.FAINT);
+      party[0].updateInfo();
+      party[1].level = 10;
+
+      const result = getHighestLevelPlayerPokemon(scene, true);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+    });
+  });
+
+  describe("getLowestLevelPokemon", () => {
+    it("gets lowest level pokemon", () => {
+      const party = scene.getParty();
+      party[0].level = 100;
+
+      const result = getLowestLevelPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+    });
+
+    it("gets lowest level pokemon at different index", () => {
+      const party = scene.getParty();
+      party[1].level = 100;
+
+      const result = getLowestLevelPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+
+    it("breaks ties by getting returning lower index", () => {
+      const party = scene.getParty();
+      party[0].level = 100;
+      party[1].level = 100;
+
+      const result = getLowestLevelPlayerPokemon(scene);
+      expect(result.species.speciesId).toBe(Species.ARCEUS);
+    });
+
+    it("returns lowest level unfainted if unfainted is true", () => {
+      const party = scene.getParty();
+      party[0].level = 10;
+      party[0].hp = 0;
+      party[0].trySetStatus(StatusEffect.FAINT);
+      party[0].updateInfo();
+      party[1].level = 100;
+
+      const result = getLowestLevelPlayerPokemon(scene, true);
+      expect(result.species.speciesId).toBe(Species.MANAPHY);
+    });
+  });
+
+  describe("getRandomSpeciesByStarterTier", () => {
+    it("gets species for a starter tier", () => {
+      const result = getRandomSpeciesByStarterTier(5);
+      const pokeSpecies = getPokemonSpecies(result);
+
+      expect(pokeSpecies.speciesId).toBe(result);
+      expect(speciesStarters[result]).toBe(5);
+    });
+
+    it("gets species for a starter tier range", () => {
+      const result = getRandomSpeciesByStarterTier([5, 8]);
+      const pokeSpecies = getPokemonSpecies(result);
+
+      expect(pokeSpecies.speciesId).toBe(result);
+      expect(speciesStarters[result]).toBeGreaterThanOrEqual(5);
+      expect(speciesStarters[result]).toBeLessThanOrEqual(8);
+    });
+
+    it("excludes species from search", () => {
+      // Only 9 tiers are: Koraidon, Miraidon, Arceus, Rayquaza, Kyogre, Groudon, Zacian
+      const result = getRandomSpeciesByStarterTier(9, [Species.KORAIDON, Species.MIRAIDON, Species.ARCEUS, Species.RAYQUAZA, Species.KYOGRE, Species.GROUDON]);
+      const pokeSpecies = getPokemonSpecies(result);
+      expect(pokeSpecies.speciesId).toBe(Species.ZACIAN);
+    });
+
+    it("gets species of specified types", () => {
+      // Only 9 tiers are: Koraidon, Miraidon, Arceus, Rayquaza, Kyogre, Groudon, Zacian
+      const result = getRandomSpeciesByStarterTier(9, null, [Type.GROUND]);
+      const pokeSpecies = getPokemonSpecies(result);
+      expect(pokeSpecies.speciesId).toBe(Species.GROUDON);
+    });
+  });
+
+  describe("koPlayerPokemon", () => {
+    it("KOs a pokemon", () => {
+      const party = scene.getParty();
+      const arceus = party[0];
+      arceus.hp = 100;
+      expect(arceus.isAllowedInBattle()).toBe(true);
+
+      koPlayerPokemon(arceus);
+      expect(arceus.isAllowedInBattle()).toBe(false);
+    });
+  });
+
+  describe("getTextWithEncounterDialogueTokens", () => {
+    it("injects dialogue tokens", () => {
+      scene.currentBattle.mysteryEncounter = new MysteryEncounter(null);
+      scene.currentBattle.mysteryEncounter.setDialogueToken("test", "value");
+
+      const result = getTextWithEncounterDialogueTokens(scene, "mysteryEncounter:unit_test_dialogue");
+      expect(result).toEqual("valuevalue @ec{testvalue} @ec{test1} value @ec{test\\} @ec{test\\} {test}");
+    });
+
+    it("can perform nested dialogue token injection", () => {
+      scene.currentBattle.mysteryEncounter = new MysteryEncounter(null);
+      scene.currentBattle.mysteryEncounter.setDialogueToken("test", "value");
+      scene.currentBattle.mysteryEncounter.setDialogueToken("testvalue", "new");
+
+      const result = getTextWithEncounterDialogueTokens(scene, "mysteryEncounter:unit_test_dialogue");
+      expect(result).toEqual("valuevalue new @ec{test1} value @ec{test\\} @ec{test\\} {test}");
+    });
+  });
+
+  describe("queueEncounterMessage", () => {
+    it("queues a message with encounter dialogue tokens", async () => {
+      scene.currentBattle.mysteryEncounter = new MysteryEncounter(null);
+      scene.currentBattle.mysteryEncounter.setDialogueToken("test", "value");
+      const spy = vi.spyOn(game.scene, "queueMessage");
+      const phaseSpy = vi.spyOn(game.scene, "unshiftPhase");
+
+      queueEncounterMessage(scene, "mysteryEncounter:unit_test_dialogue");
+      expect(spy).toHaveBeenCalledWith("valuevalue @ec{testvalue} @ec{test1} value @ec{test\\} @ec{test\\} {test}", null, true);
+      expect(phaseSpy).toHaveBeenCalledWith(expect.any(MessagePhase));
+    });
+  });
+
+  describe("showEncounterText", () => {
+    it("showText with dialogue tokens", async () => {
+      scene.currentBattle.mysteryEncounter = new MysteryEncounter(null);
+      scene.currentBattle.mysteryEncounter.setDialogueToken("test", "value");
+      const spy = vi.spyOn(game.scene.ui, "showText");
+
+      showEncounterText(scene, "mysteryEncounter:unit_test_dialogue");
+      expect(spy).toHaveBeenCalledWith("valuevalue @ec{testvalue} @ec{test1} value @ec{test\\} @ec{test\\} {test}", null, expect.any(Function), 0, true);
+    });
+  });
+
+  describe("showEncounterDialogue", () => {
+    it("showText with dialogue tokens", async () => {
+      scene.currentBattle.mysteryEncounter = new MysteryEncounter(null);
+      scene.currentBattle.mysteryEncounter.setDialogueToken("test", "value");
+      const spy = vi.spyOn(game.scene.ui, "showDialogue");
+
+      showEncounterDialogue(scene, "mysteryEncounter:unit_test_dialogue", "mysteryEncounter:unit_test_dialogue");
+      expect(spy).toHaveBeenCalledWith("valuevalue @ec{testvalue} @ec{test1} value @ec{test\\} @ec{test\\} {test}", "valuevalue @ec{testvalue} @ec{test1} value @ec{test\\} @ec{test\\} {test}", null, undefined, 0, 0);
+    });
+  });
+
+  describe("initBattleWithEnemyConfig", () => {
+    it("", () => {
+
+    });
+  });
+
+  describe("setCustomEncounterRewards", () => {
+    it("", () => {
+
+    });
+  });
+
+  describe("selectPokemonForOption", () => {
+    it("", () => {
+
+    });
+  });
+
+  describe("setEncounterExp", () => {
+    it("", () => {
+
+    });
+  });
+
+  describe("leaveEncounterWithoutBattle", () => {
+    it("", () => {
+
+    });
+  });
+
+  describe("handleMysteryEncounterVictory", () => {
+    it("", () => {
+
+    });
+  });
+});
+
diff --git a/src/test/mystery-encounter/mystery-encounter.test.ts b/src/test/mystery-encounter/mystery-encounter.test.ts
index b8f50070011..2645fbc68ce 100644
--- a/src/test/mystery-encounter/mystery-encounter.test.ts
+++ b/src/test/mystery-encounter/mystery-encounter.test.ts
@@ -1,9 +1,11 @@
-import {afterEach, beforeAll, beforeEach, describe, it, vi} from "vitest";
+import {afterEach, beforeAll, beforeEach, expect, describe, it, vi} from "vitest";
 import * as overrides from "../../overrides";
 import GameManager from "#app/test/utils/gameManager";
 import Phaser from "phaser";
+import {Species} from "#enums/species";
+import {MysteryEncounterPhase} from "#app/phases/mystery-encounter-phase";
 
-describe("Mystery Encounter", () => {
+describe("Mystery Encounters", () => {
   let phaserGame: Phaser.Game;
   let game: GameManager;
 
@@ -19,17 +21,29 @@ describe("Mystery Encounter", () => {
 
   beforeEach(() => {
     game = new GameManager(phaserGame);
-    vi.spyOn(overrides, "MYSTERY_ENCOUNTER_RATE_OVERRIDE", "get").mockReturnValue(64);
-    vi.spyOn(overrides, "STARTING_WAVE_OVERRIDE", "get").mockReturnValue(3);
+    vi.spyOn(overrides, "MYSTERY_ENCOUNTER_RATE_OVERRIDE", "get").mockReturnValue(256);
+    vi.spyOn(overrides, "STARTING_WAVE_OVERRIDE", "get").mockReturnValue(11);
   });
 
-  it("spawns a mystery encounter", async() => {
-    // await game.runToSummon([
-    //   Species.CHARIZARD,
-    //   Species.VOLCARONA
-    // ]);
-    // expect(game.scene.getCurrentPhase().constructor.name).toBe(EncounterPhase.name);
-  }, 100000);
+  it("Spawns a mystery encounter", async() => {
+    await game.runToMysteryEncounter([
+      Species.CHARIZARD,
+      Species.VOLCARONA
+    ]);
+
+    await game.phaseInterceptor.to(MysteryEncounterPhase, false);
+    expect(game.scene.getCurrentPhase().constructor.name).toBe(MysteryEncounterPhase.name);
+  });
+
+  it("", async() => {
+    await game.runToMysteryEncounter([
+      Species.CHARIZARD,
+      Species.VOLCARONA
+    ]);
+
+    await game.phaseInterceptor.to(MysteryEncounterPhase, false);
+    expect(game.scene.getCurrentPhase().constructor.name).toBe(MysteryEncounterPhase.name);
+  });
 
   it("spawns mysterious challengers encounter", async() => {
   });
diff --git a/src/test/phases/mystery-encounter-phase.test.ts b/src/test/phases/mystery-encounter-phase.test.ts
new file mode 100644
index 00000000000..8d8bac79b5a
--- /dev/null
+++ b/src/test/phases/mystery-encounter-phase.test.ts
@@ -0,0 +1,159 @@
+import {afterEach, beforeAll, beforeEach, expect, describe, it, vi} from "vitest";
+import * as overrides from "../../overrides";
+import GameManager from "#app/test/utils/gameManager";
+import Phaser from "phaser";
+import {Species} from "#enums/species";
+import {MysteryEncounterOptionSelectedPhase, MysteryEncounterPhase} from "#app/phases/mystery-encounter-phase";
+import {Mode} from "#app/ui/ui";
+import {Button} from "#enums/buttons";
+import MysteryEncounterUiHandler from "#app/ui/mystery-encounter-ui-handler";
+import {MysteryEncounterType} from "#enums/mystery-encounter-type";
+import {MysteryEncounterTier} from "#app/data/mystery-encounter";
+
+describe("Mystery Encounter Phases", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phaser.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+    vi.spyOn(overrides, "MYSTERY_ENCOUNTER_RATE_OVERRIDE", "get").mockReturnValue(256);
+    vi.spyOn(overrides, "STARTING_WAVE_OVERRIDE", "get").mockReturnValue(11);
+  });
+
+  describe("MysteryEncounterPhase", () => {
+    it("Runs to MysteryEncounterPhase", async() => {
+      await game.runToMysteryEncounter([
+        Species.CHARIZARD,
+        Species.VOLCARONA
+      ]);
+
+      await game.phaseInterceptor.to(MysteryEncounterPhase, false);
+      expect(game.scene.getCurrentPhase().constructor.name).toBe(MysteryEncounterPhase.name);
+    });
+
+    it("Runs MysteryEncounterPhase", async() => {
+      vi.spyOn(overrides, "MYSTERY_ENCOUNTER_OVERRIDE", "get").mockReturnValue(MysteryEncounterType.MYSTERIOUS_CHALLENGERS);
+      await game.runToMysteryEncounter([
+        Species.CHARIZARD,
+        Species.VOLCARONA
+      ]);
+
+      game.onNextPrompt("MysteryEncounterPhase", Mode.MYSTERY_ENCOUNTER, () => {
+        // End phase early for test
+        game.phaseInterceptor.superEndPhase();
+      });
+      await game.phaseInterceptor.run(MysteryEncounterPhase);
+
+      expect(game.scene.mysteryEncounterData.encounteredEvents.length).toBeGreaterThan(0);
+      expect(game.scene.mysteryEncounterData.encounteredEvents[0][0]).toEqual(MysteryEncounterType.MYSTERIOUS_CHALLENGERS);
+      expect(game.scene.mysteryEncounterData.encounteredEvents[0][1]).toEqual(MysteryEncounterTier.UNCOMMON);
+      expect(game.scene.ui.getMode()).toBe(Mode.MYSTERY_ENCOUNTER);
+    });
+
+    it("Selects an option for MysteryEncounterPhase", async() => {
+      vi.spyOn(overrides, "MYSTERY_ENCOUNTER_OVERRIDE", "get").mockReturnValue(MysteryEncounterType.MYSTERIOUS_CHALLENGERS);
+      const dialogueSpy = vi.spyOn(game.scene.ui, "showDialogue");
+      const messageSpy = vi.spyOn(game.scene.ui, "showText");
+      await game.runToMysteryEncounter([
+        Species.CHARIZARD,
+        Species.VOLCARONA
+      ]);
+
+      game.onNextPrompt("MysteryEncounterPhase", Mode.MYSTERY_ENCOUNTER, () => {
+        // Select option 1 for encounter
+        const handler = game.scene.ui.getHandler() as MysteryEncounterUiHandler;
+        handler.unblockInput();
+        handler.processInput(Button.ACTION);
+      });
+      await game.phaseInterceptor.run(MysteryEncounterPhase);
+
+      // After option selected
+      expect(game.scene.getCurrentPhase().constructor.name).toBe(MysteryEncounterOptionSelectedPhase.name);
+      expect(game.scene.ui.getMode()).toBe(Mode.MESSAGE);
+      expect(dialogueSpy).toHaveBeenCalledTimes(1);
+      expect(messageSpy).toHaveBeenCalledTimes(2);
+      expect(dialogueSpy).toHaveBeenCalledWith("What's this?", "???", null, expect.any(Function));
+      expect(messageSpy).toHaveBeenCalledWith("Mysterious challengers have appeared!", null, expect.any(Function), 750, true);
+      expect(messageSpy).toHaveBeenCalledWith("The trainer steps forward...", null, expect.any(Function), 750, true);
+    });
+  });
+
+  describe("MysteryEncounterOptionSelectedPhase", () => {
+    it("runs phase", () => {
+
+    });
+
+    it("handles onOptionSelect execution", () => {
+
+    });
+
+    it("hides intro visuals", () => {
+
+    });
+
+    it("does not hide intro visuals if option disabled", () => {
+
+    });
+  });
+
+  describe("MysteryEncounterBattlePhase", () => {
+    it("runs phase", () => {
+
+    });
+
+    it("handles TRAINER_BATTLE variant", () => {
+
+    });
+
+    it("handles BOSS_BATTLE variant", () => {
+
+    });
+
+    it("handles WILD_BATTLE variant", () => {
+
+    });
+
+    it("handles double battle", () => {
+
+    });
+  });
+
+  describe("MysteryEncounterRewardsPhase", () => {
+    it("runs phase", () => {
+
+    });
+
+    it("handles doEncounterRewards", () => {
+
+    });
+
+    it("handles heal phase if enabled", () => {
+
+    });
+  });
+
+  describe("PostMysteryEncounterPhase", () => {
+    it("runs phase", () => {
+
+    });
+
+    it("handles onPostOptionSelect execution", () => {
+
+    });
+
+    it("runs to next EncounterPhase", () => {
+
+    });
+  });
+});
+
diff --git a/src/test/utils/gameManager.ts b/src/test/utils/gameManager.ts
index 84d39024dc9..bfe13ee127c 100644
--- a/src/test/utils/gameManager.ts
+++ b/src/test/utils/gameManager.ts
@@ -33,6 +33,7 @@ import { Species } from "#enums/species";
 import { Button } from "#enums/buttons";
 import { BattlerIndex } from "#app/battle.js";
 import TargetSelectUiHandler from "#app/ui/target-select-ui-handler.js";
+import BattleMessageUiHandler from "#app/ui/battle-message-ui-handler";
 
 /**
  * Class to manage the game state and transitions between phases.
@@ -137,6 +138,30 @@ export default class GameManager {
     await this.phaseInterceptor.run(EncounterPhase);
   }
 
+  /**
+   * Runs the game to a mystery encounter phase.
+   * @param species - Optional array of species for party.
+   * @returns A promise that resolves when the EncounterPhase ends.
+   */
+  async runToMysteryEncounter(species?: Species[]) {
+    await this.runToTitle();
+
+    this.onNextPrompt("TitlePhase", Mode.TITLE, () => {
+      this.scene.gameMode = getGameMode(GameModes.CLASSIC);
+      const starters = generateStarter(this.scene, species);
+      const selectStarterPhase = new SelectStarterPhase(this.scene);
+      this.scene.pushPhase(new EncounterPhase(this.scene, false));
+      selectStarterPhase.initBattle(starters);
+    });
+
+    this.onNextPrompt("EncounterPhase", Mode.MESSAGE, () => {
+      const handler = this.scene.ui.getHandler() as BattleMessageUiHandler;
+      handler.processInput(Button.ACTION);
+    }, null, true);
+
+    await this.phaseInterceptor.run(EncounterPhase);
+  }
+
   /**
    * Transitions to the start of a battle.
    * @param species - Optional array of species to start the battle with.
diff --git a/src/test/utils/mocks/mocksContainer/mockContainer.ts b/src/test/utils/mocks/mocksContainer/mockContainer.ts
index 2e2b9567796..4f8a58f7251 100644
--- a/src/test/utils/mocks/mocksContainer/mockContainer.ts
+++ b/src/test/utils/mocks/mocksContainer/mockContainer.ts
@@ -33,6 +33,10 @@ export default class MockContainer {
     // same as remove or destroy
   }
 
+  removeBetween(startIndex, endIndex, destroyChild) {
+    // Removes multiple children across an index range
+  }
+
   addedToScene() {
     // This callback is invoked when this Game Object is added to a Scene.
   }
diff --git a/src/test/utils/mocks/mocksContainer/mockSprite.ts b/src/test/utils/mocks/mocksContainer/mockSprite.ts
index 2eb77f81302..ab61f88605b 100644
--- a/src/test/utils/mocks/mocksContainer/mockSprite.ts
+++ b/src/test/utils/mocks/mocksContainer/mockSprite.ts
@@ -31,6 +31,7 @@ export default class MockSprite {
     };
     this.anims = {
       pause: () => null,
+      stop: () => null,
     };
   }
 
diff --git a/src/ui/mystery-encounter-ui-handler.ts b/src/ui/mystery-encounter-ui-handler.ts
index 232d916be57..d8981f7da0d 100644
--- a/src/ui/mystery-encounter-ui-handler.ts
+++ b/src/ui/mystery-encounter-ui-handler.ts
@@ -103,7 +103,7 @@ export default class MysteryEncounterUiHandler extends UiHandler {
         if (cursor === this.viewPartyIndex) {
           // Handle view party
           success = true;
-          this.clear();
+          // this.clear();
           this.scene.ui.setMode(Mode.PARTY, PartyUiMode.CHECK, -1, () => {
             this.scene.ui.setMode(Mode.MYSTERY_ENCOUNTER, true);
             setTimeout(() => {
@@ -116,7 +116,7 @@ export default class MysteryEncounterUiHandler extends UiHandler {
         } else {
           const selected = this.filteredEncounterOptions[cursor];
           if ((this.scene.getCurrentPhase() as MysteryEncounterPhase).handleOptionSelect(selected, cursor)) {
-            this.clear();
+            // this.clear();
             success = true;
           } else {
             ui.playError();