Pacific Hagfish

Pacific Hagfish (Eptatretus stoutii)

The Pacific Hagfish is an eel-shaped, jawless fish. This ancient species evolved ~550 million years ago, during the Cambrian Period, and predates sharks and bony fish. They have a leathery skin that produces huge amounts of slime to repel predators, and feeds on polychaete worms and carrion using two pairs of teeth on horizontal cartilaginous plates. Hagfish are seen frequently at Southern Hydrate Ridge, resting on the seafloor or investigating anything that stirs up the sediment.

Reference:
https://en.wikipedia.org/wiki/Hagfish