The Devil Toilet seat

You set up a toilet, could be a public toilet, or one at a fair ( it doesnt really matter where as long as people use it ), and play certain pranks when people are on it. When people they sit down they could get electricuted, stuck to the toilet, you put cling film over the toilet, a monter pops up when they lift up the toilet seat, when they flush the toilet poo explodes everywhere. That kind of thing!