A kind of snail that sustains itself in a previously unknown way has been discovered deep in the ocean off the Antarctic coast. The snail, Gigantopelta Chessoia, evolves one of its glands to become a special kind of digestive organ, one that eventually takes up almost all the room in its shell. Bacteria grow in the new organ and these produce enough energy for the snail to survive without eating. Scientists are calling the unusual process “crypto-metamorphosis” and believe it may also be present in other organisms.