Onix basically resembles a giant chain of gray boulders. The Pokémon has a magnet in its brain that serves as an internal compass. Onix's body becomes more rounded and smoother as it grows with age. A fully grown Onix measures at an enormous 28 feet 10 inches, or 8.8 metres.
Gender differences
None.
Special abilities
It tunnels under the ground at over fifty miles per hour. Its hard head and sturdy body are the only thing that protects Onix from the tremors it causes. If Onix takes a hard enough blow and it's body falls apart, it can regrow the rest in a matter of a few weeks. It shares this trait with Arbok.
Behavior
They are very hot headed Pokémon and will constantly attack humans and Pokémon when various objects are caught in its cragged body in the wild, but under the care of trainers they will show signs of distress instead of attacking others.
Onix can be found in mountains and caves, though they prefer underground tunnels with little light. It can also be found scragged mountains and abandoned mines.
Ash and co. encountered a giantOnix in To Master the Onixpected. It was on a rampage until Bruno managed to get a Sandslash from under the Rock Snake Pokémon's "skin." Bruno captured the Onix afterward.
The Crystal Onix featured a Crystal Onix. Ash and co. helped a glass sculptor named Mateo search for it because Mateo believed it would help inspire him to be better at his craft.
In Hello Pummelo, Drake of the Orange Crew owns an Onix and he used it to fight Ash's Squirtle in the second round in the Orange League Champion match. During the battle with Squirtle, Drake's Onix dug underground and emerged to use Bind on Squirtle, but Squirtle used Withdraw followed by a Hydro Pump, soaking Drake's Onix into submission. After drenching Drake's Onix, Squirtle defeated the Onix with a Skull Bash.
Janina, Jasmine's apprentice, has an Onix in the episode Fight for the Light. Her Onix was heavily coated in wax for protection against Water attacks.
A "King Onix" was featured in Hooked on Onix. Team Rocket tricked King Onix into thinking Ash and co. were going to destroy his kingdom. When Ash managed to convince King Onix that he and his friends weren't bad by defeating it in a battle, Team Rocket tried to steal the royal Rock Snake Pokémon, but their plan was foiled, as usual.
Onix debuts in Onix is On! of the Red, Green & Blue arc as Brock's main Pokémon, however a picture of it is showed on a leaflet in Wanted: Pikachu!. Onix later continues to make appearances with Brock in various volumes onwards.
Bruno owns an Onix, on which he battles Bill, Lt. Surge and Red on Cerise Island. The Onix later manages to carry Bruno and Koga off the collapsing island. Another wild Onix was also seen on Cerise Island.
Onix is obtainable in a Poké Ball. Once thrown, it flies up into the sky and uses Rock Throw on the player's opponents. This will hit everyone on the field except Kirby if he uses his down special move.
Onix is the second Poké Float to appear. It provides a horizontally flat area all the time it is on-screen, though it becomes diagonal as it leaves the screen.
Game data
Pokédex entries
This Pokémon was unavailable prior to Generation I.
Onix has a magnet in its brain. It acts as a compass so that this Pokémon does not lose direction while it is tunneling. As it grows older, its body becomes increasingly rounder and smoother.
Onix has a magnet in its brain. It acts as a compass so that this Pokémon does not lose direction while it is tunneling. As it grows older, its body becomes increasingly rounder and smoother.
There is a magnet in its brain that prevents an Onix from losing direction while tunneling. As it grows older, its body becomes steadily rounder and smoother.
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Onix and Swablu are the only dual-typed Pokémon that have their primary type change during evolution.
By being under the ownership of Bruno in Generation II, Onix is one of the few unevolved Pokémon that can evolve in the same generation as that of the Elite Four member to whom it belongs, the others being Dragonair, Shelgon, Haunter, and Sealeo. However, it's the only one where the Elite Four member doesn't own its evolved form.
Of all the Pokémon that can evolve, Onix has the highest base Defense.
Onix is the largest Pokémon that can legally hatch from an egg.
Origin
Onix is most likely based on a snake.
Name origin
Onix's name is a corruption of onyx, a mineral. Its Japanese name may be a combination of 岩 iwa, rock, and スネ−ク snake.
It has been suggested that Onix is based on a wyrm, a type of dragon that has been presented as limbless and burrowing. However, Onix was unable to learn DragonBreath until Generation III.
This Pokémon article is part of Project Pokédex, a Bulbapedia project that aims to write comprehensive articles on each Pokémon species, as well as Pokémon groups and forms.