That reminds me of something I did in 6th grade. I told somebody "I have a little magic trick that can make you resist the natural human urge to want money. Just hand me a dollar bill, and I can make it so you don't even want it back!". They handed me the dollar bill, and I muttered a few little nonsense words, and...........then I wiped my ass with it! Then I said "NOW, do you find that the urge is still there? Do you want it back?". Of course, he let me keep it! It was a pretty cruel joke, though.