Onix, known as the Rock Snake Pokémon, is a giant chain of gray boulders, with a rocky spine on its head. The Pokémon has a magnet in its brain that serves as an internal compass, which helps it keep direction while burrowing. Onix's body becomes more rounded and smoother as it grows with age, as well as getting harder, as it absorbs many of the hard objects it encounters while digging. It tunnels under the ground at over fifty miles per hour, in search of food. Onix can commonly be found in mountains and caves because the Onix can camouflage itself in them.