Even in the dark zone of the ocean there is some light. If you turn off the submersible headlights, you can see a pyrotechnic display in the deep sea. These flashing lights are generated by animals - this is bioluminescence. A deep sea angler fish flashes in the darkness. The light is generated by bacteria that live permanently inside the fish's lures, and attracts prey to sets of murderous teeth. There are all sorts of lures out in the darkness. It's not easy to see the purpose of one that's suspended on a long rod way below its owners terrifying teeth, but then this monster does have another giant flashing lure close to its mouth. These fish are called anglers because the fish use their lures much like a fly fisherman uses their imitation flies. For a hunting squid with huge eyes, the glimmers are intriguing - they might just be food. But for a fish with a highly extendable stomach, the lured in squid makes a satisfying meal. With thanks to the Woods Hole Oceanographic Institution (WHOI).