Charybdis (Barotrauma)

The Charybdis is a very large, whale-sized carnivorous creature found within the abyssal zones of Europa's vast oceans. While larger than other predators like the Tiger Thresher, they are still considered prey to even larger animals.

Biology
Overall, these eyeless creatures unusually resemble an upside-down, massive whale, with octopus-like tentacles, just larger than a Coelanth, with giant tentacles, dark fins, and a mouth full of silver teeth. Its curved limbs, in contrast to its dark leathery body, have a shiny set of scales.

Behavior
As it is named after a Greek mythological sea monster, the Charybdis is unusually quick despite its huge size. Predatory, it is capable of sensing vibrations within the water around it to find its prey, which may include Humans, which it can kill and eat with one bite, and severely damage vessels just as easily.

Although a predator in its own right, it's hypothesized that its body structure allows it to play dead in the presence of even larger predators.