#208 in the National Pokédex, Steelix is the Iron Snake Pokémon. It evolves from Onix, the Rock Snake Pokémon, naturally trading Onix’s Rock/Ground dual-type for Steel/Ground instead. This process occurs when an Onix is compressed by extreme pressure, as Steelix is known to live over 3000 feet underground. This makes Steelix’s body harder than diamond, with super strength to boot!