diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index f0486a8f111..53d4b6c54d2 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -1226,10 +1226,15 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
   /**
    * Checks if the {@linkcode Pokemon} has is the specified {@linkcode Species} or is fused with it.
    * @param species the pokemon {@linkcode Species} to check
+   * @param formKey If provided, requires the species to be in that form
    * @returns `true` if the pokemon is the species or is fused with it, `false` otherwise
    */
-  hasSpecies(species: Species): boolean {
-    return this.species.speciesId === species || this.fusionSpecies?.speciesId === species;
+  hasSpecies(species: Species, formKey?: string): boolean {
+    if (Utils.isNullOrUndefined(formKey)) {
+      return this.species.speciesId === species || this.fusionSpecies?.speciesId === species;
+    }
+
+    return (this.species.speciesId === species && this.getFormKey() === formKey) || (this.fusionSpecies?.speciesId === species && this.getFusionFormKey() === formKey);
   }
 
   abstract isBoss(): boolean;
@@ -3204,6 +3209,11 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
     return maxForms.includes(this.getFormKey()) || (!!this.getFusionFormKey() && maxForms.includes(this.getFusionFormKey()!));
   }
 
+  isMega(): boolean {
+    const megaForms = [ SpeciesFormKey.MEGA, SpeciesFormKey.MEGA_X, SpeciesFormKey.MEGA_Y, SpeciesFormKey.PRIMAL ] as string[];
+    return megaForms.includes(this.getFormKey()) || (!!this.getFusionFormKey() && megaForms.includes(this.getFusionFormKey()!));
+  }
+
   canAddTag(tagType: BattlerTagType): boolean {
     if (this.getTag(tagType)) {
       return false;
diff --git a/src/ui/command-ui-handler.ts b/src/ui/command-ui-handler.ts
index f23cc78c9f7..20cffbbe30a 100644
--- a/src/ui/command-ui-handler.ts
+++ b/src/ui/command-ui-handler.ts
@@ -10,6 +10,7 @@ import { globalScene } from "#app/global-scene";
 import { TerastallizeAccessModifier } from "#app/modifier/modifier";
 import { Type } from "#app/enums/type";
 import { getTypeRgb } from "#app/data/type";
+import { Species } from "#enums/species";
 
 export enum Command {
   FIGHT = 0,
@@ -180,9 +181,11 @@ export default class CommandUiHandler extends UiHandler {
 
   canTera(): boolean {
     const hasTeraMod = !!globalScene.getModifiers(TerastallizeAccessModifier).length;
+    const activePokemon = globalScene.getField()[this.fieldIndex];
+    const isBlockedForm = activePokemon.isMega() || activePokemon.isMax() || activePokemon.hasSpecies(Species.NECROZMA, "ultra");
     const currentTeras = globalScene.arena.playerTerasUsed;
     const plannedTera = globalScene.currentBattle.preTurnCommands[0]?.command === Command.TERA && this.fieldIndex > 0 ? 1 : 0;
-    return hasTeraMod && (currentTeras + plannedTera) < 1;
+    return hasTeraMod && !isBlockedForm && (currentTeras + plannedTera) < 1;
   }
 
   toggleTeraButton() {