Hagfish are like eels with a slimy coat on their bodies that keep predators from killing them. Hagfish have been around longer than dinosaurs. Hagfish survived because their slime kept them from being eaten by sharks and other predators. When anything bites down on the Hagfish, they get a mouth full of sticky slime and they choke until the predator dies or until the slime comes out.
If I saw a hagfish, I would swim as fast as possible and not look back. I’m smart enough to know not to bite it. At least it’s not a Lamprey. Lampreys are creepy little suckers because they suck out your blood. They rarely sucks out all the blood from it’s prey.