Pokémon

Pokémon are a non-Mario species, which is currently made up of 718 members, in the Pokémon series, that each have unique abilities. There are eighteen different elemental types of Pokémon; each element affects the Pokémon's attacks, abilities, and weaknesses. For example, Pikachu, being an Electric Pokémon, specializes in electrical attacks, which can easily defeat Flying and Water Pokémon, but in turn are weak against Grass Pokémon and ineffective against Ground Pokémon. Another factor that separates Pokémon from traditional animals is that after meeting certain conditions, the Pokémon will evolve into a different Pokémon. For example, a Pichu can evolve into a Pikachu with high friendship, and a Pikachu can then later evolve into its final form Raichu with a Thunder Stone. Pokémon live in the wild but are caught by Pokémon Trainers to have as pets or to battle with other Pokémon competitively.

Some select Pokémon have interacted with characters in the Mario series, most notably in the Super Smash Bros. competitions. Not only are some competitors, but if a player throws a Poké Ball, then a random Pokémon comes out and affects the gameplay in some way. These Poké Ball Pokémon don't directly hurt the player who sent them out, with the exception of Electrode and Wobbuffet.

Super Smash Bros. Competitors

 * Pikachu - (All)
 * Jigglypuff - (All)
 * Pichu - (Melee)
 * Mewtwo - (Melee)
 * Pokémon Trainer - (Brawl) While not a Pokémon himself, he uses his three Pokémon to fight:
 * Squirtle
 * Ivysaur
 * Charizard
 * Lucario - (Brawl, 3DS/Wii U'')

Saffron City Pokémon
On the Saffron City stage, there is a small garage on the right side of the stage. Most of the time, the gate to the garage is closed, but when it opens, it means one of the following Pokémon will show up in a short time. Characters entering the garage will cause a Pokémon to attack immediately.

Saffron City Background Pokémon

 * Pidgey
 * Fearow
 * Moltres
 * Butterfree

Poké Floats Pokémon

 * Squirtle
 * Onix
 * Psyduck
 * Chikorita
 * Weezing
 * Slowpoke
 * Porygon
 * Wooper
 * Sudowoodo
 * Snorlax
 * Venusaur
 * Seel
 * Wobbuffet
 * Unown
 * Goldeen
 * Lickitung
 * Chansey
 * Geodude

Pokémon Stadium 2 Background Pokémon

 * Dugtrio (Ground)
 * Cubone (Ground)
 * Hoppip (Flying)
 * Skarmory (Flying)
 * Drifloon (Flying)
 * Snorunt (Ice)
 * Snover (Ice)
 * Magnezone (Electric)
 * Electivire (Electric)

Spear Pillar Pokémon

 * Dialga (Diamond)
 * Palkia (Pearl)
 * Cresselia

In Spear Pillar, one of the three Pokémon above will appear periodically to attack fighters or change the stage itself. Dialga can slow down time as well as create a red burst of energy from its body, damaging fighters. Palkia can reverse the stage, also reversing the controls. Palkia can also change the gravity of the arena. Both Pokémon can cause parts of the stage to crumble, rotate the stage anywhere from slightly (both Dialga and Palkia), to 180 degrees (Palkia only), and create a laser beam that will damage players.

Cresselia is somewhat rarer and its only attacks are flinging large crescent-moon shaped barbs around the stage and shooting a moon-like boomerang. It cannot alter the stage in any of the ways Dialga and Palkia can.

Spear Pillar Background Pokémon

 * Uxie
 * Mesprit
 * Azelf

Subspace Emissary Pokémon

 * Rayquaza (boss)

Trivia

 * All of the Pokémon that appear in Poké Balls in Super Smash Bros. Melee are based on their design in the game Pokémon Stadium 2.
 * Additionally, in Super Smash Bros. Brawl, the 3rd generation Pokémon and 4th generation Pokémon that pop out of Poké Balls are based on their designs from the games Pokémon Colosseum and Pokémon Battle Revolution.
 * The 3rd generation is the only Pokémon generation that has yet to produce a playable Smash Bros. character.
 * In Black and White, the move Thrash hits in the melody of the first few notes of the Super Mario Bros. level theme.