diff --git a/orleans/Adventure/AdventureGrains/MonsterGrain.cs b/orleans/Adventure/AdventureGrains/MonsterGrain.cs
index 713994e422a..6f9e7239783 100644
--- a/orleans/Adventure/AdventureGrains/MonsterGrain.cs
+++ b/orleans/Adventure/AdventureGrains/MonsterGrain.cs
@@ -1,25 +1,27 @@
-using AdventureGrainInterfaces;
+using AdventureGrainInterfaces;
 
 namespace AdventureGrains;
 
-public class MonsterGrain : Grain, IMonsterGrain
+public class MonsterGrain : Grain, IMonsterGrain, IDisposable
 {
     private MonsterInfo _monsterInfo = new();
+    private IGrainTimer? _timer;
     private IRoomGrain? _roomGrain; // Current room
 
     public override Task OnActivateAsync(CancellationToken cancellationToken)
     {
         _monsterInfo = _monsterInfo with { Id = this.GetPrimaryKeyLong() };
 
-        RegisterTimer(
+        _timer = RegisterGrainTimer(
             _ => Move(),
-            null!,
             TimeSpan.FromSeconds(150),
             TimeSpan.FromMinutes(150));
 
         return base.OnActivateAsync(cancellationToken);
     }
 
+    public void Dispose() => _timer?.Dispose();
+
     Task IMonsterGrain.SetInfo(MonsterInfo info)
     {
         _monsterInfo = info;