The deep ocean can have a certain haunting quality about it. There are strange creatures down there, hiding in the darkness, waiting to emerge from the shadows. It's a realm of perpetual night filled with ghostly inhabitants, including the vampire squid.

In the depths, the vampire squid billows and undulates, stretching its arms to expand the web of skin that connects them. The fleshy spines contained within this cloak, revealed by its movements, are called cirri, and they only add to its ominous appearance. If you venture into the vampire squid's lightless world, you may see its huge, clear eyes peering back at you, gleaming blue in the lights of Nautilus Live's remotely operated vehicle.

It waits down there, not for opportunities to suck the blood of live prey as vampires do, but to collect marine snow with its long, strange feeding filament as it rains down from the ocean waters above, which may not sound especially ghastly, but the truth is that this vampire makes at least some of its living off the dead, because marine snow includes dead and rotting organic matter. To survive on this unpredictable diet, the vampire squid has evolved an extremely efficient metabolism, the slowest of any cephalopod.

Depending on where you've encountered the vampire, it may be dark red or black in color, but it won't change its shade like its cousins the octopuses and squids. It has lost the muscles that control its color-changing abilities. And, yes, for all that it's called a vampire squid, it's actually only a relative and not a real member of either of those groups. Though, it is closer to the octopuses than to the squid whose name it bears.

The lineage of the vampire squid is ancient, stretching back to the deepest evolutionary split between its ancestors and the ancestor of all octopuses, and sometimes we can see that kinship when certain octopuses of the deep sea float into view, like this cirroteuthid. It lives in the sunless depths of the ocean, down where the vampire squid dwells, drifting along in the cold water, and, like its cousin, it also possesses a cloak of skin stretched between its arms, as well as two flapping fins.

Have they ever encountered each other, I wonder? Have they ever locked eyes in the deep? We don't know much about these strange octopuses. Perhaps they haven't captured our imagination in the same way the vampire squid has, but these oceanic journeys have given us a glimpse into their dark world, a world filled with eerie creatures living out their lives in a place untouched by the sun, which is, of course, how vampires prefer it.

Before you go, you should know that we still have Bizarre Beast calendars available for sale. Get yours now at ComplexlyCalendars.com. Thanks for joining us again on our exploration of the marine realm. We'll be back on the first Friday of next month with another episode of Bizarre Beasts.