diff --git a/data/items.ts b/data/items.ts
index 9cbb084daf..110ae125c3 100644
--- a/data/items.ts
+++ b/data/items.ts
@@ -4576,7 +4576,13 @@ export const Items: {[itemid: string]: ItemData} = {
 		fling: {
 			basePower: 100,
 		},
-		onUpdate(pokemon) {
+		onStart(pokemon) {
+			if (!pokemon.ignoringItem() && this.field.getPseudoWeather('trickroom')) {
+				pokemon.useItem();
+			}
+		},
+		onAnyPseudoWeatherStart() {
+			const pokemon = this.effectState.target;
 			if (this.field.getPseudoWeather('trickroom')) {
 				pokemon.useItem();
 			}
diff --git a/sim/dex-conditions.ts b/sim/dex-conditions.ts
index 5706e86225..5f9b928bf8 100644
--- a/sim/dex-conditions.ts
+++ b/sim/dex-conditions.ts
@@ -375,6 +375,7 @@ export interface EventMethods {
 	onAnyNegateImmunity?: ((this: Battle, pokemon: Pokemon, type: string) => boolean | void) | boolean;
 	onAnyOverrideAction?: (this: Battle, pokemon: Pokemon, target: Pokemon, move: ActiveMove) => string | void;
 	onAnyPrepareHit?: CommonHandlers['ResultSourceMove'];
+	onAnyPseudoWeatherStart?: (this: Battle, target: Pokemon, source: Pokemon, pseudoWeather: Condition) => void;
 	onAnyRedirectTarget?: (
 		this: Battle, target: Pokemon, source: Pokemon, source2: Effect, move: ActiveMove
 	) => Pokemon | void;
diff --git a/sim/field.ts b/sim/field.ts
index 07925d8585..2057a431fa 100644
--- a/sim/field.ts
+++ b/sim/field.ts
@@ -208,6 +208,7 @@ export class Field {
 			delete this.pseudoWeather[status.id];
 			return false;
 		}
+		this.battle.runEvent('PseudoWeatherStart', source, source, status);
 		return true;
 	}
 
diff --git a/test/sim/items/roomservice.js b/test/sim/items/roomservice.js
new file mode 100644
index 0000000000..f46f4eb0a0
--- /dev/null
+++ b/test/sim/items/roomservice.js
@@ -0,0 +1,35 @@
+'use strict';
+
+const assert = require('./../../assert');
+const common = require('./../../common');
+
+let battle;
+
+describe('Room Service', function () {
+	afterEach(function () {
+		battle.destroy();
+	});
+
+	it(`should activate when Trick Room is set`, function () {
+		battle = common.createBattle([[
+			{species: 'slowpoke', item: 'roomservice', moves: ['sleeptalk']},
+		], [
+			{species: 'whimsicott', item: 'roomservice', moves: ['trickroom']},
+		]]);
+		battle.makeChoices();
+		assert.statStage(battle.p1.active[0], 'spe', -1);
+		assert.statStage(battle.p2.active[0], 'spe', -1);
+	});
+
+	it(`should activate after entrance Abilities`, function () {
+		battle = common.createBattle([[
+			{species: 'slowpoke', moves: ['teleport']},
+			{species: 'ditto', ability: 'imposter', item: 'roomservice', moves: ['transform']},
+		], [
+			{species: 'whimsicott', ability: 'prankster', moves: ['trickroom']},
+		]]);
+		battle.makeChoices();
+		battle.makeChoices();
+		assert.statStage(battle.p1.active[0], 'spe', -1, `Ditto-Whimsicott should be at -1 Speed after transforming`);
+	});
+});