The bottom of the ocean can be a strange place, an alien landscape inhabited by weird creatures, unlike anything that lives on land.

In some places, the seafloor is made up of vast stretches of barren sand or rocks, yet life still thrives down there. Life like this little blob. ♪♪ INTRO ♪♪ Thanks for coming to another undersea tour on Bizarre Beasts.

This is an animal known as a sea pig. It’s a kind of sea cucumber that lives in the deep ocean, a soft-bodied marine invertebrate that is, in the simplest terms, just a living tube that gets around on little tube-feet. Much of a sea pig’s life is spent shuffling through the sediment on the bottom of the sea.

There, it uses its feeding tentacles to find and consume bits of dead and decaying organic matter, things like the whale fall we encountered in our last episode. And while they may not look like it, sea pigs are echinoderms, members of the group that also includes pointier creatures like sea stars and sea urchins. But this sea pig isn’t tethered to life on the reef or seafloor, the way its cousins often are.

It isn’t held together by hardened plates, rigid or flexibly articulated. Its hard parts exist as little spicules of calcium carbonate, sprinkled throughout the walls of its body. No, it can swim, flexing and flopping its tube-shaped body to and fro, like a single hand trying to clap or a wing trying to beat.

It’s not clear where it’s trying to go or what it’s trying to get away from, or whether all of this flapping serves another purpose, like helping move food through its simple gut and exit as, well, poop. The remotely-operated vehicle driven by our friends at Nautilus Live that captured this footage also managed to catch this sea pig at its least glamorous moment, but it is a living animal, after all, and it’s just doing what almost all animals do. Like so many creatures of the deep ocean, this sea pig is mostly translucent, though tinted a sandy brownish-gold, and tinged here and there by pops of orange, like on the tips of its tentacles.

Many other sea pigs are more pinkish, like the animal they’re named for. Its clear body means that its insides are largely on display, including the loops that form the tube-within-a-tube that is its digestive system. And while it may seem obvious and intuitive to us that the sea pig has a front end and a back end, that’s not so common for echinoderms.

One of the shared features of this ancient group is its radial symmetry, that they’re symmetrical around a central axis. Except when they aren’t, like this sea pig. For some evolutionary reason, sea cucumbers also have some bilateral symmetry, like we do, with left and right side that mirror each other.

So, while the sea pig is, in many ways, very much one of the stranger creatures that populates the depths of our oceans, in other ways, it is unexpectedly familiar. We hope you’re enjoying these new kinds of experimental Bizarre Beasts episodes. We’ll be back on the first Friday of next month with one of our regular videos. ♪♪ OUTRO ♪♪