I had an bone in my hand randomly decide to eat itself a few years ago (aneurysmal bone cyst), which required two surgeries to fix (one to biopsy, the other to replace what was left of the bone fragments with a titanium rod and bone cement), and they wouldn't let me watch them do either surgery. Now, thanks to this linked video, I don't have to imagine anymore what it might have looked like.

I should note, the linked article doesn't really accurately describe my personal experience with this disease process. I was told by my docs at the time that it normally happens in kids around 9 or so when they start their growth spurts going into puberty, and it normally happens in the long bones, such as just below the shoulders or in the femurs. Mine happened in the left ring finger metacarpal bone when I was 29. The cyst developed and grew large enough to shatter the bone completely, then it proceeded to reabsorb the fragments back into itself. This left me with the end of a bone swinging freely into the meat of my hand. It got to where I couldn't lift a jug of milk or push open a car door. Doctors at first just thought I was a drug seeking slacker who didn't want to work, regardless of the fact there was a distinct lump on my hand that didn't exist on the other. Took them a month to finally see the problem in an x-ray, after which they really got on the ball to get it fixed. I got do to all sorts of neat tests, like a full body nuclear bone scan to see if any of my other bones were also randomly eating themselves. Fortunately, they weren't, but after that scan, I can now say I know what if feels like to be microwaved. Now I have a wicked cool scar on my hand and a ring finger that's about an eighth of an inch shorter than it used to be.

Also: I now have a permanent file at the Mayo Clinic. Heh. :)