Vampyroteuthis infernalis, not because it sucks blood but "because they have the ability to ‘cape’ themselves up with their membrane, which is black underside, looking just like a vampire wearing a black cape!" More
Vampire squid have eight webbed arms, tipped with suckers and lined with fleshy spines (called cirri), and two retractable sensory filaments. When threatened, it inverts so that the cirri point outwards in a menacing fashion.
Bioluminescent Octopus-One of the few known octopods known to be bioluminescent (glow with its own light) this Stauroteuthis syrtensis octopus was found about a half mile deep in the Gulf of Maine. Photophores (light-emitting organs) may be positioned to fool prey into swimming right into the mouth of the hunter.