Oh, I'm very sorry! Did Marilulu get stuck in the wall after trying to walk off the head of the rat? That should be fixed already! I'm sorry about that! If the problem persist, please tell me and I'll fix it :)
(I'll tell you a secret: If you want to get to him again very fast, you can press shift and click anywhere to "teleport". I used this to debug the game but left it in as a little cheat code. Please don't abuse this and don't tell anyone!)