Maybe hagfish, otherwise known as slime eels. A deep sea scavenger that sometimes crosses over and eats the living if they slow down too much.
With the charismatic name, they seem perfect for a horror movie.
If you want to appreciate hagfish, don't touch, that's what makes the world class slime come out in unbelievable amounts.
These fish are survivors, basically unchanged for millions of years. Now these noble but unsavory fish are actively sought by fishermen, and they're overfished in some areas.
For you slime geeks, the slime is an amazing product, composed of mucous (proteoglycans) and made tougher by some long and extremely thin threads up to 60 cm long and 1.5 micrometers thick (about 1/100 of a human hair. Slime scientist D. S. Fudge can tell you more about slime if you really want to know.