Unidan, AKA Ben Eisenkop, is an ecosystem ecologist who first rose to fame (infamy?) on Reddit by popping up in posts across the site, answering any queries and concepts pertaining to biology and ecology. Eisenkop is a columnist for Upvoted, where he spotlights a new creature every week.

Today’s bizarre beast is, well, bizarre. Even before we get to what makes them particularly cool, just their name is a little odd: the sea cucumber. No, they bear no relation to the gourd vegetable that you slice over your salads, but they do bear a resemblance to the overall shape, which is where the name comes from.

While most are a plain tentacle tube-like shape, there is a wild variety of sea cucumbers, which range from leopard spotted ones to “furry” ones and even some that are shorter and rounded, earning them the name of “sea apples” like Pseudocolochirus violaceus.

You might be saying to yourself, “Uh, Unidan, cucumbers are vegetables, why didn’t they say sea potatoes?”

Well, that’s because the name sea potato was already taken by Echinocardium cordatum, a type of sea urchin.

Sea cucumbers are relatively mellow creatures, extending a delicate, multi-branched apparatus into the water column to filter out organic material to eat, which can be readily tucked back inside of themselves should danger arise. Should danger persist, however, some sea cucumbers can pull out all the stops.

If harassed enough, some sea cucumbers are capable of, quite literally, eviscerating themselves to throw their guts at their would-be predators. Long specialized strands of their gut, located underneath their respiratory tree, called Cuvierian tubules (named after the French biologist, Georges Cuvier, who discovered them) are forcefully ejected out of their anuses at their attackers. These tubules become highly lengthened and highly adhesive upon contact with the sea water, causing them to tangle and ensnare any predator that doesn’t flee the scene.

In addition, these tubules are sometimes ejected with a dose of holothurin, a noxious chemical with properties similar to soap, which causes an adverse reaction in most sea life. You can watch the gut-wrenching behavior at work here in a video courtesy of National Geographic:

Luckily for the sea cucumber, ripping out your own guts through your butt isn’t as bad as it sounds. While the predator is tangled up, the sea cucumber is able to make its escape, and new tubules will regenerate within the gut within a few weeks!