Adding a UI to set the type on startup can be added easily. # ---- class myPlayer(GameTypes.KX_GameObject): def die(self): # ... do stuff ... self.endObject() # make an instance player = myPlayer(gameOb) # gameOb is made invalid now. player.die() # ---- One limitation (which could also be an advantage), is making the subclass instance will return that subclass everywhere, you cant have 2 different subclasses of the same BGE data at once.