An out of left-field idea. It doesn't happen a lot, but one of the things people fear deeply is being bitten by a shark. Sharks sometimes bite surfers, because, it is suspected that 4 paddling arms lying on a surfboard triggers the "tasty seal" match in the shark's brain.
(Reportedly sharks don't actually like how we taste that much, and have spit out human limbs they bit off. I dunno, but somehow that's adding insult to major injury.)