This parasitic flatworm is very difficult to detect, owing to a unique camouflage mechanism that's reminiscent of what the alien does to its prey in The Thing.

According to a new study published by researchers at the University of Southampton, the worm camouflages itself with the undigested remains of its prey. Because its prey are coral reefs, that means it can become virtually indistinguishable from its environment.

One of the researchers, Jörg Wiedenmann—who is the head of the university's coral reef laboratory—says the biology of the worm (Amakusaplana acroporae) is "amazing":

By using molecular biological techniques, we found out how the worm accomplishes this excellent camouflage: When eating the coral tissue it also takes up the symbiotic alga of the coral. Instead of digesting them completely, it keeps a certain number of them alive and distributes them in its guts so that it perfectly mimics the appearance of the coral. Moreover, it also incorporates the green fluorescent protein pigments that lend the glowing greenish coloration to the coral host to perfect its camouflage.

This Worm Can Make Itself Virtually Invisible

Awesome! I'm so glad that we've found a real-life equivalent to the body-stealing alien in John Carpenter's The Thing. For now, the critter has been found in the wild only in one location on the Great Barrier Reef. However, it has also infested the tanks of aquarium hobbyists, who have seen entire coral cultures wiped out in a short period of time.

Since the parasite has no known natural predators, the researchers warn that measures should be taken to keep it quarantined—and that includes making aquarium hobbyists aware of the risks associated with returning the inhabitants of their tanks to the ocean. Otherwise, Amakusaplana acroporae might launch an invisible invasion of other coral reefs.