here's plan B. get a bag, where they usually put bread in, and put it at home. wait for a day yuou are sure he's alone at home, poo into the bag, put the bag in front of his door, rind the bell and put the bag on fire. It doesn't give him anything at all, no scars or financial losses, but it's so funny, my mate just panicked when i did it with him yesterday xD like 'fire, fire, waaaaahhh'