Minecraft - THE BEST TRAP EVER ??

This is, atleast with my knowledge, the best trap ever.
It kills the griefer 100%, and nobody will know HOW he die. Well, unless they watch this :P.
It also collects about 55% of the items from the griefer. So that's pretty good. He will just think that his stuff glitched out. :)
NOTE: THIS DOES NOT WORK ANYMORE SINCE MINECRAFT 1.4.4!