One popular circus stunt in southeast Asia is a demonstration of superior animal training involving a man or woman placing their head into the open jaws of a crocodile. It's one of those stunts that if it goes bad, it goes really bad.
And this dude found out the hard way. The croc clamps down hard on the guy's head, and luckily he is able to get his head out of there. He does suffer a pretty gnarly wound.