There is a method in Class Actor called getOneIntersectingObject and several others that might fit your situation. You can use these methods to sense when one object intersects another. Maybe make a method based on the ever popular crab scenario's canSee method, whose code is downloadable (although they usually use the less useful getOneObjectAtOffset). My game, PyroTyro, uses the first method. The code is available; just open the House class. After one car "canSee" another (they collide), you can remove both of their images and replace them with a crunched up car image, just as I have replaced my House image with a burning house image after the House canSee the match.