Think of the weirdest, creepiest, coolest creature you could imagine. Chances are, the ocean already has something like it. And that animal probably lives in the deep sea.

The mysterious gulper eel, also known as the pelican eel, is one of the most unusual deep-sea animals. The gulper eel might look like your run-of-the-mill eel: it has a long, narrow body that undulates back and forth to move through the water. Like other true eels, they are part of the order Anguilliformes, which contains 800 species including moray and garden eels. They are black in color and can reach about 2-3 feet in length, which isn’t that significant compared to other eel species (the largest eel species is the European conger, which can reach up to almost 20 feet long!) They live in the deep sea, ranging from 1,600 to almost 10,000 feet below the surface.

However, gulper eels don’t need flashy colors or impressive size to stand out in the eel crowd. They have a trick up their sleeves (fins?) that makes them unlike any other eel species.

Gulper eels get their name from their massive, gulping mouth. If you haven’t seen it already, watch the video below from the E/V Nautilus when they spotted a gulper eel feeding off of Papahānaumokuākea Marine National Monument. It’s like an eel was combined with a massive black balloon.

So why do gulper eels have this unusual adaptation? Like pelicans (and the inspiration for gulper eels’ other name), it allows them to scoop up water into its mouth to swallow prey whole. They primarily feed on crustaceans, fish and cephalopods, but some scientists believe their wide mouth allows them to go after larger fish if food is hard to find.

These eels are rare, so we don’t know too much about them. But they are found all over the world and are considered by the IUCN as a species of “least concern”, which means they are thought to be at risk of extinction. We need more deep-sea research to learn about these weird and wonderful eels.

Check out more weird deep sea critters here.