This is actually a small cephalopod that maxes out at one foot in length and resides in extreme deep sea conditions throughout the world’s temperate and tropical oceans. It has bioluminescent organs, and its unique two retractile filaments place it in an order apart from both octopi and squid. It is the only member of its order. (The name comes from its dark coloring and cloak-like webbing, not it’s eating habits – it feeds on detritus, not blood.)