diff --git a/OpenRa.Game/WorldUtils.cs b/OpenRa.Game/WorldUtils.cs
index 36f18f485b..c4aca9bcf4 100755
--- a/OpenRa.Game/WorldUtils.cs
+++ b/OpenRa.Game/WorldUtils.cs
@@ -27,7 +27,8 @@ namespace OpenRa
 
 		public static bool IsActorCrushableByActor(this World world, Actor a, Actor b)
 		{
-			return world.IsActorCrushableByMovementType(a, b.traits.GetOrDefault<IMovement>().GetMovementType());
+			var movement = b.traits.GetOrDefault<IMovement>();
+			return movement != null && world.IsActorCrushableByMovementType(a, movement.GetMovementType());
 		}
 		
 		public static bool IsActorPathableToCrush(this World world, Actor a, UnitMovementType umt)