Killer Coconut
 

Hate to repeat stories from another web site but this is curtesy of AikiFaqs and had me laughing severely at work (when I should have been working):

"...third one all I had, shomenuchi, and sure enough, it cracked -- cracked just enough to allow the edge of my hand to squeeze in, then snapped shut like ball-headed pit bull. I'm sure it was quite a sight, me hopping around hollering with a damned coconut chomped down on my hand. When I finally got the vicious fruit off, I was left with a lovely blood blister."

More info on silly demos at:

http://www.aikidofaq.com/stories/silly_demo.html