diff --git a/src/data/ability.ts b/src/data/ability.ts
index c0b412a0249..f786754bbf0 100644
--- a/src/data/ability.ts
+++ b/src/data/ability.ts
@@ -4693,28 +4693,24 @@ export class TerrainEventTypeChangeAbAttr extends PostSummonAbAttr {
     }
     const currentTerrain = pokemon.scene.arena.getTerrainType();
     const typeChange: Type[] = [];
-    let isRevert: boolean = false;
-    if (currentTerrain !== TerrainType.NONE) {
-      switch (currentTerrain) {
-      case TerrainType.ELECTRIC:
-        typeChange.push(Type.ELECTRIC);
-        break;
-      case TerrainType.MISTY:
-        typeChange.push(Type.FAIRY);
-        break;
-      case TerrainType.GRASSY:
-        typeChange.push(Type.GRASS);
-        break;
-      case TerrainType.PSYCHIC:
-        typeChange.push(Type.PSYCHIC);
-        break;
-      default:
-        pokemon.getTypes(false, false, true).forEach(t => {
-          typeChange.push(t);
-        });
-        isRevert = true;
-        break;
-      }
+    switch (currentTerrain) {
+    case TerrainType.ELECTRIC:
+      typeChange.push(Type.ELECTRIC);
+      break;
+    case TerrainType.MISTY:
+      typeChange.push(Type.FAIRY);
+      break;
+    case TerrainType.GRASSY:
+      typeChange.push(Type.GRASS);
+      break;
+    case TerrainType.PSYCHIC:
+      typeChange.push(Type.PSYCHIC);
+      break;
+    default:
+      pokemon.getTypes(false, false, true).forEach(t => {
+        typeChange.push(t);
+      });
+      break;
     }
     if (typeChange.length !== 0) {
       if (pokemon.summonData.addedType && typeChange.includes(pokemon.summonData.addedType)) {
@@ -4725,15 +4721,22 @@ export class TerrainEventTypeChangeAbAttr extends PostSummonAbAttr {
     }
     let message: string = "";
     const pokemonName = getPokemonNameWithAffix(pokemon);
-    if (isRevert) {
+    if (currentTerrain === TerrainType.NONE) {
       message = i18next.t("abilityTriggers:pokemonTypeChangeRevert", { pokemonNameWithAffix: pokemonName });
     } else {
       const typeName = i18next.t(`pokemonInfo:Type.${Type[typeChange[0]]})`);
-      message = i18next.t("abilityTriggers:pokemonTypeChange", { pokemonNameWithAffix: pokemonName, typeName: typeName });
+      message = i18next.t("abilityTriggers:pokemonTypeChange", { pokemonNameWithAffix: pokemonName, moveType: typeName });
     }
     pokemon.scene.queueMessage(message);
     return true;
   }
+
+  applyPostSummon(pokemon: Pokemon, passive: boolean, simulated: boolean, args: any[]): boolean | Promise<boolean> {
+    if (pokemon.scene.arena.getTerrainType() !== TerrainType.NONE) {
+      return this.apply(pokemon, passive, simulated, new Utils.BooleanHolder(false), []);
+    }
+    return false;
+  }
 }
 
 async function applyAbAttrsInternal<TAttr extends AbAttr>(
diff --git a/src/test/abilities/mimicry.test.ts b/src/test/abilities/mimicry.test.ts
index a067665e0b5..3b442491d36 100644
--- a/src/test/abilities/mimicry.test.ts
+++ b/src/test/abilities/mimicry.test.ts
@@ -1,6 +1,7 @@
 import { Abilities } from "#enums/abilities";
 import { Moves } from "#enums/moves";
 import { Species } from "#enums/species";
+import { Type } from "#app/data/type";
 import GameManager from "#test/utils/gameManager";
 import Phaser from "phaser";
 import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
@@ -23,20 +24,52 @@ describe("Abilities - Mimicry", () => {
     game = new GameManager(phaserGame);
     game.override
       .moveset([ Moves.SPLASH ])
-      .ability(Abilities.BALL_FETCH)
+      .ability(Abilities.MIMICRY)
       .battleType("single")
       .disableCrits()
       .enemySpecies(Species.MAGIKARP)
-      .enemyAbility(Abilities.BALL_FETCH)
       .enemyMoveset(Moves.SPLASH);
   });
 
-  it("should do X", async () => {
-    await game.classicMode.startBattle([ Species.FEEBAS ]);
+  // List of Tests (Work in Progress)
+  // Pokemon should return to original root type even when transformed when terrain ends
+  // The effect of Forest's Curse is removed when Mimicry activates in Grassy Terrain
+  it("Mimicry activates after the Pokémon with Mimicry is switched in while terrain is present, or whenever there is a change in terrain", async () => {
+    game.override.enemyAbility(Abilities.MISTY_SURGE);
+    await game.classicMode.startBattle([ Species.FEEBAS, Species.ABRA ]);
+
+    const playerPokemon1 = game.scene.getPlayerPokemon();
+    game.move.select(Moves.SPLASH);
+    await game.toNextTurn();
+    expect(playerPokemon1?.getTypes().includes(Type.FAIRY)).toBe(true);
+
+    game.doSwitchPokemon(1);
+    await game.toNextTurn();
+
+    const playerPokemon2 = game.scene.getPlayerPokemon();
+    expect(playerPokemon2?.getTypes().includes(Type.FAIRY)).toBe(true);
+  });
+
+  it("Pokemon should revert back to its original, root type once terrain ends", async () => {
+    game.override
+      .moveset([ Moves.SPLASH, Moves.TRANSFORM ])
+      .enemyAbility(Abilities.MIMICRY)
+      .enemyMoveset([ Moves.SPLASH, Moves.PSYCHIC_TERRAIN ]);
+    await game.classicMode.startBattle([ Species.REGIELEKI ]);
+
+    const playerPokemon1 = game.scene.getPlayerPokemon();
+    game.move.select(Moves.TRANSFORM);
+    await game.forceEnemyMove(Moves.PSYCHIC_TERRAIN);
+    await game.toNextTurn();
+    expect(playerPokemon1?.getTypes().includes(Type.PSYCHIC)).toBe(true);
+
+    if (game.scene.arena.terrain) {
+      game.scene.arena.terrain.turnsLeft = 1;
+    }
 
     game.move.select(Moves.SPLASH);
-    await game.phaseInterceptor.to("BerryPhase");
-
-    expect(true).toBe(true);
+    await game.forceEnemyMove(Moves.SPLASH);
+    await game.toNextTurn();
+    expect(playerPokemon1?.getTypes().includes(Type.ELECTRIC)).toBe(true);
   });
 });