​This six-gill shark (Hexanchus) was filmed during a submersible dive off the northeast coast of Molokai at a depth of 1000m (3280ft). The 2 red laser dots are 6 inches apart, resulting in a length of about 18 ft for the shark.
Great ecstatic live commentary by University of Hawaii Oceanography Professor Jeff Drazen!
Many thanks to Dr. Craig Smith (University of Hawaii) and Dr. Eric Vetter for permitting release of this footage which was obtained as part of their research data set.
http://www.soest.hawaii.edu/oceanography/faculty/csmith/

Six-gill sharks, like this one off the coast of Vancouver, cruise the ocean floor during the day, sometimes as deep as 8,200 feet (2,500 meters), then move toward the surface at night to feed. They can reach impressive lengths of 16 feet (4.8 meters) on a diet of other sharks, rays, squids, crabs, and occasionally seals.