#0095 · Kanto · Generation 1

Onix

Rock Snake Pokémon · Rock/Ground-type

Onix is a Rock/Ground-type Pokémon, the Rock Snake Pokémon, number 95 (#0095) in the National Pokédex. It was introduced in Generation 1 and comes from the Kanto region. It is 8.8 m tall and weighs 210 kg.

Onix is the Rock Snake Pokémon, a towering chain of boulders with a magnet in its brain that works as a compass, so it never gets lost while tunnelling. In Generation I it is the tallest Pokémon of all.

How to pronounce Onix

Onix is pronounced ON-iks. The capital letters show the stressed syllable.

Listen to Onix said out loud:

In Japanese it is イワーク (Iwark).

Hear every other name on the Pokémon pronunciation guide.

Lore

Biology

Onix is a long chain of grey boulders that shrink towards the tail, with a rocky spine on its head. It is 8.8 m long and weighs 210 kg. The Pokédex says its stone hardens with age until it resembles black diamond, and older Onix grow rounder and smoother.

Behaviour

Onix is a restless digger. The Pokédex says it bores through the ground at 80 km/h (50 mph) with a roar that carries far, and that Diglett move into the tunnels it leaves.

Habitat

The Pokédex places it underground. It is not available in Scarlet and Violet. In Legends: Z-A it lives in Wild Zone 14 in Magenta District, and it appears in the Mega Dimension DLC's Hyperspace Lumiose.

Diet

The Pokédex says it feeds on boulders and swallows soil as it tunnels, and that the hard objects it absorbs make it solid.

Powers

Rock Head spares it recoil from moves like Head Smash, Sturdy lets it survive a hit from full health, and the hidden Weak Armor swaps Defense for Speed when a physical move lands. It uses Rock Slide, Iron Head and Stealth Rock. With 160 base Defense but only 35 HP and 30 Special Attack, it is a tough wall that hits softly.

Name origin

Onix may come from onyx, the mineral. Its Japanese name is Iwark (イワーク), which may blend iwa ('rock') with 'bulwark' or 'snake'.

Design inspiration

Bulbapedia offers a few readings: a pun on 'rock python', an earthworm (its soil-eating underground life suits the worm best), and a limbless dragon like the lindworm, since it learns Dragon Breath. These are fan readings.

Evolution notes

Onix becomes Steelix when traded holding a Metal Coat, or, in Legends: Arceus, when a Metal Coat is used on it.

In the games

Onix is the ace of Brock, the first Gym Leader in Red and Blue, and Bruno of the Elite Four fields two in the same games. In Legends: Arceus, wild Onix turn up in space-time distortions and massive mass outbreaks.

In the anime

Onix appears in the very first episode, 'Pokémon - I Choose You!'. Brock's Onix, introduced in 'Showdown in Pewter City', is his partner in Kanto and Johto before he gives it to his brother Forrest. 'The Crystal Onix' follows a glass sculptor's search for a crystal Onix.

Fun facts

• Bulbapedia says Onix has the highest base Defense of any Pokémon that can still evolve.
• Bulbapedia says Onix's is the only multi-stage line fully obtainable by in-game trades, and only in HeartGold and SoulSilver: Bellsprout for Onix in Violet City, then any Pokémon at all for Steelix in Olivine City.
• In the Pokémon Stadium games, Onix can twist its head or any other part of its body a full turn.

Sources: Bulbapedia: Onix (Pokémon) · Serebii: Onix (Scarlet/Violet Pokédex)

Base stats

• HP: 35
• Attack: 45
• Defense: 160
• Sp. Atk: 30
• Sp. Def: 45
• Speed: 70

Onix’s base stat total is 385. Its highest stat is Defense.

Type matchups

What is Onix weak to?

Onix takes extra damage from Water (4×), Grass (4×), Ice (2×), Fighting (2×), Ground (2×), Steel (2×) moves.

It resists Poison (¼×), Normal (½×), Fire (½×), Flying (½×), Rock (½×).

It is immune to Electric moves.

Evolution

How does Onix evolve?

Onix evolves into Steelix (Trade holding Metal Coat).

The whole family: Onix, Steelix.

Abilities

• Rock Head: Protects against recoil damage.
• Sturdy: Prevents being KOed from full HP, leaving 1 HP instead. Protects against the one-hit KO moves regardless of HP.
• Weak Armor (hidden ability): Raises Speed and lowers Defense by one stage each upon being hit by a physical move.

Moves

Moves Onix learns by level up in Sword / Shield

TM moves (40)

Onix can learn 40 moves from TMs in Sword / Shield: Dig, Screech, Self-Destruct, Rest, Rock Slide, Snore, Protect, Scary Face, Attract, Sandstorm, Sunny Day, Facade, Rock Tomb, Sand Tomb, Rock Blast, Payback, Round, Bulldoze, Brutal Swing, Stomping Tantrum, Breaking Swipe, Body Slam, Earthquake, Substitute, Endure, Sleep Talk, Iron Tail, Taunt, Dragon Dance, Gyro Ball, Dragon Pulse, Earth Power, Flash Cannon, Iron Head, Stone Edge, Stealth Rock, Heavy Slam, Drill Run, High Horsepower, Body Press.

Egg moves (7):Block, Defense Curl, Dragon Tail, Flail, Head Smash, Rollout, Wide Guard.

Move tutor moves (2): Meteor Beam, Scorching Sands.

Breeding & training

• Gender: 50% male, 50% female.
• Egg groups: Mineral.
• Egg cycles: 25 (steps to hatch, Scarlet/Violet: 3,200).
• Catch rate: 45 out of 255.
• Base friendship (Gen 8 onward): 50.
• Growth rate: Medium (1,000,000 experience points to reach level 100).
• Defeating it gives 1 Defense effort value.
• Base experience yield: 77.

Pokédex entries

This chain of immense stones resembles a giant serpent. Tremors shake the earth above as it burrows deep beneath the ground, feeding on boulders as it goes. (Legends: Arceus)

It rapidly bores through the ground at 50 mph by squirming and twisting its massive, rugged body. (Silver, SoulSilver, Shield)

As it digs through the ground, it absorbs many hard objects. This is what makes its body so solid. (Crystal, Sword)

Burrows at high speed in search of food. The tunnels it leaves are used as homes by Diglett. (X, Let’s Go, Pikachu!, Let’s Go, Eevee!)

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. (Ruby, Sapphire, Omega Ruby, Alpha Sapphire)

It usually lives underground. It searches for food while boring its way through the ground at 50 miles per hour. (FireRed, Y)

Names around the world

Trivia

• Tallest Rock type: 8.8 m.
• Tallest Pokémon in Gen 1: 8.8 m.
• Tallest Ground type in Gen 1: 8.8 m.
• Highest Defense among Ground types in Gen 1: 160.
• Tallest Rock type in Gen 1: 8.8 m.
• Highest Defense among Rock types in Gen 1: 160.
• Taller than 99% of all Pokémon (8.8 m).
• Heavier than 92% of all Pokémon (210 kg).
• Base stat total 385, ranked #653 of 1,025.
• Its best stat is Defense, ranked #9 of 1,025.
• One of 9 Pokémon that are both Rock and Ground.
• One of 107 gray Pokémon.
• Number 95 of 151 Pokémon introduced in Generation 1 (Kanto).
• Part of an evolution family of 2 Pokémon.
• Can learn 59 different moves in Sword / Shield.
• Catch rate 45: about 5.9% per Poké Ball at full health.
• Appears in 15 distinct Pokédex entries.

Sources and fact-checking

• Stats, types, abilities, moves, evolutions, forms and Pokédex entries: PokéAPI open game data.
• Lore: written by pokee.si in our own words, researched from Bulbapedia: Onix (Pokémon), Serebii: Onix (Scarlet/Violet Pokédex).
• Pronunciation (ON-iks): it follows how the English anime, games or official videos say it.

Last checked: 19 October 2026. Every sentence of the lore was checked against Bulbapedia, Serebii and the game data.

Explore

Rock-type Pokémon · Ground-type Pokémon · Rock/Ground weaknesses and matchups · Kanto region guide · Rock Head ability · Sturdy ability · Weak Armor ability · Compare Onix · Full Pokédex · Type chart · All moves

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Gen 1 Rock-type Pokémon · Gen 1 Ground-type Pokémon · Gen 1 Pokémon list · Gray Pokémon list · Mineral egg group · Pokémon that start with O · Snake Pokémon

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