From Bulbapedia, the community-driven Pokémon encyclopedia.
Brock's Steelix (Japanese: タケシのハガネール Takeshi's Haganeil) was the first Pokémon acquired by Brock in the anime, and is his main battling Pokémon in both the anime and games.
In the anime
Its voice actor in both Japanese and English is 石塚運昇 Unshō Ishizuka.
Brock received it as an Onix as a present from his father, Flint, during his tenth birthday, as seen in a flashback in A Wailord of a Time!.
Like most of Brock's Pokémon, Onix received very little screentime in comparison to the Pokémon of the other main characters. This may have been due to its massive size, although it did have an impressive battle against Iron-Masked Marauder's Tyranitar in Celebi: Voice of the Forest. Its size was also used in several ways, such as a staircase in Pokémon Shipwreck. Like most of Brock's pre-Hoenn Pokémon, Onix does not have a distinct personality.
Brock ended up giving Onix and two of his other Pokémon to his eldest sibling, Forrest, who took on the role of Gym Leader at Pewter City. When Brock returned to the gym in Grating Spaces, Onix had evolved into a Steelix under Forrest's care.
Moves used
In the games
Steelix, in both of its forms, has appeared in every game that Brock has appeared in, and is Brock's main Pokémon in each of those games.
First battle
Second battle
Round 1
Round 2
Round 1
Round 2
In the manga
In the Pokémon Adventures manga
Brock with Onix in Pokémon Adventures.
In Pokémon Adventures, Red challenges Brock's Onix during Onix is On! in a gym battle to gain the Boulder Badge. Red uses Pika to battle, but it is still angry with Red for capturing it. Onix first uses Rock Throw at Pika, causing massive damage before proceeding to use its body like a torpedo to hit Pika with Skull Bash; Red pushes Pika out of the way. Trying again, Pikachu uses a powerful electric attack on Onix, breaking apart the rocks that its body is composed of.
Brock would later use Onix in an exhibition match against Jasmine, where it was soundly defeated by her Steelix.
In the Electric Tale of Pikachu manga
Since Electric Tale of Pikachu is based on the anime, Onix appeared in this manga in Ash and Brock's Gym battle in Play Misty For Me. It lost the battle.
In the Pokémon Pocket Monsters manga
In Pokémon Pocket Monsters, Brock's Onix appears in Take Out The Rival Onix, in Isamu Akai's battle with Brock.
In the Pokémon Zensho manga
In Pokémon Zensho, Satoshi battles Brock's Onix in Nibi City. Satoshi uses his Charmander in the battle, and tells it to chop the horn-like part of Onix's head off. Onix is then defeated, and Satoshi wins the battle.
In the TCG
Brock's Steelix was featured in the TCG multiple times. The following is a list of cards named Brock's Onix.
Trivia
Related articles
For more information on this Pokémon's species, see Onix and Steelix.