Onix

Physiology
Onix is a Rock Snake Pokémon. Its serpentine body is made up of large boulders and little pebbles. It has a long horn atop its head and small eyes.

Natural abilities
Onix can have the abilities Rock Head or Sturdy. Rock Head prevents Onix from recoiling, while Sturdy gives Onix immunity to OHKO moves . When it is burrowing underground, it can cause rumbles and earthquakes. It can dig at speeds up to 50 MPH. It has a compass in its brain that can tell Onix what direction it is facing.

Evolution
Onix evolves into Steelix when traded while holding a Metal Coat.