Onix is a Rock/Ground-type Pokémon introduced in the first generation of the Pokémon series. It resembles a large serpent made of boulders and is known for its impressive speed and strength. Onix evolves into Steelix when traded while holding a Metal Coat, gaining Steel-type attributes. In the Pokémon games, Onix is often found in caves and mountainous areas. It has the ability to burrow through the ground, making it a skilled digger. Onix is also known for its high Defense stat, allowing it to withstand many physical attacks during battles.