The LA Times has a story about the amazing Humboldt squid. There are tens of millions of them, invading the coast of California and worrying fisheries officials.
I'm with PZ Myers on this one: they're apparently mugging divers for bling.
Four divers found that out when they tried to document the squids' behavior in the Sea of Cortez 17 years ago. While a non-diving passenger battled to land a 14-foot thresher shark on rod-and-reel, Alex Kerstitch of Arizona and three friends submerged in the nighttime sea, carrying cameras. The divers settled near the dim fringes of the boat's lights. They could see the weary shark being pulled toward the boat. Below, dozens of squid began flashing iridescently, red-white-red.
A squid grabbed his right swim fin and pulled downward. He kicked it away but another grabbed his head. The cactus-like tentacles found his neck, the only part of his body not covered with neoprene.
He bashed the squid with his dive light, far less bright than the movie lights, and it let go, but it swiped both the light and the gold chain he'd been wearing.
Kerstitch was released by the squid, and made it back to the boat wounded but alive.