Onix is a Pokémon composed of a giant chain of gray boulders that become smaller towards the tail. Its length makes it the tallest Rock-type Pokémon. It has black eyes and a rounded snout. On top of its head is a rocky spine. As it grows older, it becomes more rounded and smoother, eventually becoming similar to black diamonds. Inside its brain is a magnet that serves as an internal compass, guiding Onix wherever they need to go and prevents them from getting lost while digging. (Source: Bulbagarden.net, CC BY-NC-SA)