【Watch Scandal Sin in the City (2001)】

Hidden beneath its tusk-like shell is Watch Scandal Sin in the City (2001)a jet-black, slippery and slimy sea creature that looks like it came off the set of Alien.

Scientists said on Monday that they've discovered the first living specimen of a giant shipworm in a Philippine bay.

People have known of the huge mollusc for hundreds of years, by the shells they've left behind that were the size of baseball bats. But scientists have only seen dead specimens.

"To me, [finding the giant shipworm] is almost like finding a dinosaur -- something that was pretty much only known by fossils," Dan Distel, research professor at Northeastern University, told the Guardian.

Distel and his team published the find on Monday in the Proceedings of the National Academy of Sciences. The discovery, they said, is akin to finding the "unicorn" of mollusks.

Another team member, Margo Haygood, a research professor in medicinal chemistry at the University of Utah College of Pharmacy, said they were led to the discovery by a 2011 Filipino documentary that showed local divers gathering the huge shipworms and cooking them.

Haygood told Popular Sciencethat the team discovered a population of the shipworms, and sent five of them to a laboratory, where they opened the giant shipworm's hard, calcified tube.

She said it was nearly as heavy as a branch. A fully-grown shipworm can reach up to a metre (3.3 ft) long.

Unlike its shipworm cousins, which burrow into rotting wood, this giant shipworm, K. polythalamia lives on hydrogen sulfide, that which gives eggy farts their potent kick.

K. polythalamia rarely eats anything else -- its digestive system is stunted, and scientists have found little to no fecal matter in its body.

Hydrogen sulfide -- released from decaying vegetation and rotting animals in the swamps where it lives -- is digested by symbiotic bacteria that lives in the giant shipworm's outsize gills. The bacteria then produces carbon compounds the giant shipworm consumes.

There are still many questions about the giant shipworm -- for instance, scientists have yet to discover its life cycle, and how to measure its age.

"Are the specimens we studied a couple years old, or a couple hundred?" Haygood told Popular Science.

The mollusk's discovery shows how little we know about life on Earth, she added. "Isn't it remarkable that you can find such a bizarre creature in the 21st century? I'm in favor of investigating alien life, but we should put just as much effort into figuring out life down here."