Oh, you should plant, like, springy monsters that look like mutated pigs in a blanket in the toybox so when they open the box they'll totally lose it.
That'll learn 'em.
Once when I was a kid my mom made me clean my room really good. Between my desk and my bookcase, clear in the back, was an Easter egg that had fallen. This was some time after Easter. It didn't stink until I disturbed it. Man....whew!