A lovely threat, from Geoffrey Pullum in an update to this Language Log entry:

“Your skin will break out in boils; your teeth will itch where you can’t reach to scratch them; your car will develop an annoying whiny rattle that will stop whenever a mechanic listens; your bananas will go directly from green to black without passing through yellow; your country music albums will play backwards so that your dog comes back to life… I’m warning you, bad shit will happen all over in your life. Don’t test me.”

It’s the bit about the bananas that really drives the stake home for me.  Bananas are tricky enough without voodoo.