diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index 1d58f7de883..03521359ce4 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -2200,6 +2200,9 @@ export abstract class Pokemon extends Phaser.GameObjects.Container {
     if (this.isFusion() && ability.hasAttr("NoFusionAbilityAbAttr")) {
       return false;
     }
+    if (this.isTransformed() && ability.hasAttr("NoTransformAbilityAbAttr")) {
+      return false;
+    }
     const arena = globalScene?.arena;
     if (arena.ignoreAbilities && arena.ignoringEffectSource !== this.getBattlerIndex() && ability.ignorable) {
       return false;
diff --git a/test/abilities/shields-down.test.ts b/test/abilities/shields-down.test.ts
index 77cec525442..ff07f2c9560 100644
--- a/test/abilities/shields-down.test.ts
+++ b/test/abilities/shields-down.test.ts
@@ -74,7 +74,7 @@ describe("Abilities - Shields Down", () => {
 
     minior.hp = 0;
     minior.status = new Status(StatusEffect.FAINT);
-    expect(minior.isFainted()).toBe(true);
+    expect(minior).toHaveFainted();
 
     game.move.use(MoveId.SPLASH);
     await game.doKillOpponents();
@@ -176,15 +176,15 @@ describe("Abilities - Shields Down", () => {
     expect(game.field.getPlayerPokemon()).toHaveBattlerTag(BattlerTagType.CONFUSED);
   });
 
-  // TODO: The `NoTransformAbilityAbAttr` attribute is not checked anywhere, so this test cannot pass.
-  // TODO: Move this to a transform test
-  it.todo("should not activate when transformed", async () => {
+  it("should not activate when transformed", async () => {
     game.override.enemyAbility(AbilityId.IMPOSTER);
     await game.classicMode.startBattle([SpeciesId.MINIOR]);
 
     game.move.use(MoveId.SPORE);
     await game.toEndOfTurn();
 
-    expect(game.field.getEnemyPokemon()).toHaveStatusEffect(StatusEffect.SLEEP);
+    const karp = game.field.getEnemyPokemon();
+    expect(karp).not.toHaveAbilityApplied(AbilityId.SHIELDS_DOWN);
+    expect(karp).toHaveStatusEffect(StatusEffect.SLEEP);
   });
 });