Onix

Onix is a snake-like Pokémon that is made up of boulders. Onix is one of the original 151 Pokémon, and it debuts in the Generation I games, Pocket Monsters Red and Green Versions. It appears in the first two Super Smash Bros. games, Super Smash Bros. and Super Smash Bros. Melee, although it is only a Poké Ball Pokémon in the former game.

Background information
In the Pokémon franchise, Onix is a Rock/Ground-type Pokémon that is number 095 in both the Kanto Pokédex and the National Pokédex. Onix's evolution, Steelix, was introduced in the Generation II games, Pokémon Gold and Silver Versions.

The move used by Onix in Super Smash Bros., Rock Throw, is a move that it can learn in every games, starting with Generation I at level 19.

Super Smash Bros.
In Super Smash Bros., Onix is a common Poké Ball summon. It attacks by using Rock Throw, in which it moves to the top of the stage and rains boulders down onto opponents. If an opponent touches Onix or its boulders, they take knockback damage from Onix.

An Onix is shown in the background of Pikachu's congratulations screen.

Super Smash Bros. Melee
In Super Smash Bros. Melee, during the opening cinematic, there is a brief scene where several Pokémon are shown, and an Onix can be seen to the right. In the Poké Floats stage, Onix is the second Pokémon float to appear during a cycle. Like other floats, fighters use the Onix float as a platform. The Onix float is lifelike, especially because it rotates its boulder segments.