Myxinidae

Hagfish, belonging to the family Myxinidae, are primitive, eel-like marine vertebrates found in cold waters worldwide. They lack jaws and bones, possessing cartilaginous skeletons and round mouths with horny teeth. Hagfish have poorly developed eyes and a single nostril. They feed on dead animals and invertebrates, often by burrowing into their prey. A notable defense mechanism is the secretion of copious amounts of slime from glands along their bodies when disturbed, which can deter predators and sometimes cause problems for fishermen.123