The Atlantic Hagfish is a uniquely gross sea creature which has been called the Slime Eel for its special ability to be very very icky. One hagfish, which is a snake-like fish, not an eel, about 18 inches long, can produce enough thick gooey slime to fill a milk jug in one go.
The slime is different than any other sort of goo produced by snails or other creatures. It’s the roughest, toughest slime around and filled with tiny fibers that give it extra strength and sticking power. It is believed that the slime is used to make a protective covering (really, who would want to touch that?) and can even clog the gills of fish that get too nosy.
When a hagfish wants to clean itself it can tie its own body in a knot and squeeze the slime off as the knot is slid down to the tail.
To add to their gross-out effect, they feed by attaching to a passing fish, burrowing under the skin and licking away the flesh with a raspy tongue. You’re welcome for that image.