Onix basically resembles a giant chain of gray boulders, with a rocky spine on its head. 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 meters.
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 its 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 craggy body. However, domesticated Onix 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 in craggy mountains and abandoned mines. It is most common in Kanto, Johto, and Sinnoh.
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.
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 shown 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.
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.
Onix is the largest and heaviest Pokémon that evolves once.
Onix, in Generation I, is the highest-level non-legendary wild Pokémon available without the use of a glitch that the Pokédex has recorded data on its location. Onix can be found in Kanto's Victory Road at level 49.
However, Ditto up to level 65 can be found in the Cerulean Cave, but in the Generation I games, the Pokédex does not inform the player of the Pokémon available in the cave, as Pokémon only found there would just display as "Area Unknown" in the Area section of the Pokédex.
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 that has no pre-evolution. Snorlax originally held this distinction until Generation IV when Munchlax was introduced.
Onix is one of four Pokémon which changes its primary type upon evolution (from Rock to Steel). The others are Azurill, Swablu and Eevee.
Onix and Swablu are also the only dual-typed Pokémon that have their primary type change during evolution.
In addition, Onix is the only Pokémon whose evolved form has a type-advantage against its predecessor, without that type being identical to both Pokémon (such as Dragon or Ghost).
Origin
Onix is most likely based on a combination of a snake and earthworm. It may also been based on the wyrm, a type of dragon that has been presented as limbless and burrowing.
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.
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.
Hard Stone (5%)
For other sprites and images, please see Onix images on Bulbagarden Archives.
