diff --git a/src/modifier/modifier-type.ts b/src/modifier/modifier-type.ts
index d83b5c6835f..b5574c02c8b 100644
--- a/src/modifier/modifier-type.ts
+++ b/src/modifier/modifier-type.ts
@@ -2822,10 +2822,7 @@ const modifierPool: ModifierPool = {
       modifierTypes.MYSTICAL_ROCK,
       (party: Pokemon[]) => {
         return party.some(p => {
-          const moveset = p
-            .getMoveset(true)
-            .filter(m => !isNullOrUndefined(m))
-            .map(m => m.moveId);
+          const moveset = p.getMoveset(true).map(m => m.moveId);
 
           const hasAbility = [
             Abilities.DRIZZLE,
diff --git a/test/items/mystical_rock.test.ts b/test/items/mystical_rock.test.ts
index 91fd6405704..0558bc21fe1 100644
--- a/test/items/mystical_rock.test.ts
+++ b/test/items/mystical_rock.test.ts
@@ -1,5 +1,4 @@
 import { globalScene } from "#app/global-scene";
-import { MoveEndPhase } from "#app/phases/move-end-phase";
 import { Moves } from "#enums/moves";
 import { Abilities } from "#enums/abilities";
 import { Species } from "#enums/species";
@@ -25,37 +24,37 @@ describe("Items - Mystical Rock", () => {
     game = new GameManager(phaserGame);
 
     game.override
-      .enemySpecies(Species.MAGIKARP)
+      .enemySpecies(Species.SHUCKLE)
       .enemyMoveset(Moves.SPLASH)
       .enemyAbility(Abilities.BALL_FETCH)
       .moveset([Moves.SUNNY_DAY, Moves.GRASSY_TERRAIN])
       .startingHeldItems([{ name: "MYSTICAL_ROCK", count: 2 }])
       .battleType("single");
-  }, 20000);
+  });
 
   it("should increase weather duration by +2 turns per stack", async () => {
     await game.classicMode.startBattle([Species.GASTLY]);
 
     game.move.select(Moves.SUNNY_DAY);
 
-    await game.phaseInterceptor.to(MoveEndPhase);
+    await game.phaseInterceptor.to("MoveEndPhase");
 
     const weather = globalScene.arena.weather;
 
     expect(weather).toBeDefined();
     expect(weather!.turnsLeft).to.equal(9);
-  }, 20000);
+  });
 
   it("should increase terrain duration by +2 turns per stack", async () => {
     await game.classicMode.startBattle([Species.GASTLY]);
 
     game.move.select(Moves.GRASSY_TERRAIN);
 
-    await game.phaseInterceptor.to(MoveEndPhase);
+    await game.phaseInterceptor.to("MoveEndPhase");
 
     const terrain = globalScene.arena.terrain;
 
     expect(terrain).toBeDefined();
     expect(terrain!.turnsLeft).to.equal(9);
-  }, 20000);
+  });
 });