The frilled shark
it's 01 of 02 extant species of shark in the family Chlamy-doselachidae, with a wide but patchy distribution in the Atlantic & Pacific Oceans.
It has been caught as deep as 1,570 m, although it is uncommon below 1,200 m. The long jaws of the frilled shark are highly distensible with an extremely wide gape, allowing it to swallow whole prey over one-half its size. Humans rarely encounter frilled sharks, which prefer to remain in the oceans' depths, up to 5,000 feet below the surface.
image from http://oceana.org/marine-life/sharks-rays/frilled-shark