Hagfish are primitive marine creatures that live deep at the bottom of the ocean. They look a bit like an eel and have no jaws, spines or scales and have exceedingly poor eyesight; most rely on their sense of smell. Over 60 different species of hagfish are known which can vary in color from pinks, browns or greys. They often scavenge off dead animals, but they can also latch onto passing live prey, burrowing inside and eating their way out. Grim. One of the most interesting features of hagfish is their ability to produce a slime that can suffocate predators such as sharks. Just a tiny amount of slime will dramatically expand in size when it comes into contact with seawater, and sometimes the hagfish themselves can get tangled up but they wriggle into knots to escape from it.
A headless goddamned ghost appears right in goddamned front of them. You literally see it materialize on camera -- of all the entries on this list, this is the one you absolutely have to watch (here's a shorter version that cuts right to the ghost if you don't have 4 free minutes). Seriously, your mind will be blown like Eric Stoltz's penis in The Rules of Attraction. As they swing the camera lazily through the room, the ghost just walks very purposefully toward them like it's delivering a pizza, while a long, low moan emanates from its phantom lungs.