The deep-sea divers have seen them ... Found at depths of 3,000 to 6,000 feet, the gulper eel, also known as the "pelican eel," has a slender body and insanely huge mouth, resembling a pelican ...

The frilled shark, a rare deep-sea “living fossil,” resembles an eel and was spotted in 2007 near Japan's surface, possibly due to illness or disorientation. In 2014, a goblin shark ...