With its terrifying extendable jaw, the viper dogfish would could a xenomorph crap its pants.
The viper dogfish is a rarely seen small shark that lives at great depth, where all of the sea's most frightening creatures hang out. It was first discovered in 1986, according to National Geographic. On the rare occasions when it is seen, it's usually by accident. The smiley little killer pictured above was one of five dredged up off the coast of Taiwan recently. They were discovered during a fish survey conducted by a local institute.
A 2003 study determined the viper dogfish is characterized by extendable jaws used to reach out and snatch prey, as well as horrifyingly sharp teeth. Additionally, they have distinctive marks on the underside that can glow in the dark. They're lunge feeders (or ram feeders), according to NatGeo, which means they hunt by swimming quickly at their prey with an open mouth. They often swallow their victims whole.
All of the ones caught in this group ranged from eight to ten inches long. The largest on record was 18 inches long. So, it's no great white, but you probably don't want to challenge one to a leg wrestling competition. They'd probably take offense and then haunt your dreams for eternity like Freddie Krueger. (See a couple more photos here.)
h/t National Geographic