Vampire Squid Vampyroteuthis infernalis
This is the only squid that spends its entire life in deep, oxygen-poor water.
Like many deep-living creatures, the vampire squid is bioluminescent and has light organs, or photophores, on the tips of its arms and at the base of its fins.
If threatened, it flashes these lights and writhes around in the water, finally ejecting mucus that sparkles with blue luminescent light. When the lights go out, the vampire squid will have vanished. Its predators include sea lions and deep-diving whales.