I was at the beach with my legs in the water, on kind of a dock/pier thing. A shark approached and circled the pier and I thought I was fine. Then the end of the pier dipped into the water, and it swam up the submerged pier and started to attack. I kicked its nose (I remembered something about that from a TV show or magazine article) and it left. Then it circled back and came again. Its face fell off and it had teeth and knobby stubs of teeth behind a flesh-covered but mechanical looking sub-face. I ran away. But when I got away from the water I looked at my calf and it had a gaping hole in it. It looked like the flesh of my calf was hollow and I could see blood and bone sloshing around inside. It didn't bother me *too* much, there was no pain, but I was sure that was because the damage was so bad. I covered it up with a rag and ran around looking for medical help.