From the Super Mario Wiki
Rayquaza is a legendary Dragon/Flying-type Pokémon from the Pokémon series. It is the cover-mascot of the game Pokémon Emerald. It appears in the Subspace Emissary of Super Smash Bros. Brawl.
In Subspace Emissary, it suddenly emerges from a lake after hearing Diddy Kong, who had been looking at the nearly destroyed Arwing nearby. It attacks the Arwing with Dragon Pulse and snatches Diddy in its claws. Diddy screams for help, whereas Fox McCloud, who manages to escape the damaged Arwing, leaps from the Arwing and breaks Diddy free of Rayquaza's grasp using Fox Illusion. Rayquaza, furious, ends up using Dragon Pulse on McCloud, who deflects it with Reflector, flinging it back at Rayquaza, who falls back into the lake.
McCloud and Diddy engage in a fight with Rayquaza, resulting in the second main boss fight of the Subspace Emissary. Some of its attacks involve burrowing into the ground and then bursting upwards. It will also fly with great speed horizontally over the stage and will sometimes drop a Thunder attack. The player can beat it by attacking it around the head. When Rayquaza uses Dragon Pulse, the player can use Fox's Reflector to counter it. Although Rayquaza does not appear to have any connections with the Subspace Army, it is fought again in The Great Maze.
Rayquaza is also the only non-playable Pokémon and non-Poké Ball Pokémon to get its own Sticker.
Super Smash Bros. Brawl Trophy Information
|| GBA Pokémon Ruby & Sapphire
|| A Sky High Pokémon. It normally resides high up in the ozone layer where it flies endlessly, so it is rarely seen. However, when Groudon and Kyogre began to fight, it appeared to calm them down. It has the ability Air Lock, which blocks all weather-condition effects. It has exceedingly strong abilities, and its attack power is especially remarkable.
| GBA Pokémon Emerald
Super Smash Bros. Brawl Sticker Information
|| Pokémon series
|| [Aura] - Attack +24|
Usable by: Lucario
Names in Other Languages
|Rayquaza; from 烈空者(れっくうしゃ/rekkuusha), meaning "one who tears the sky" and 座(ざ/za), meaning "seat".
|Rayquaza; transliteration from Japanese name.
- Unlike other bosses of the Subspace Emissary mode, Rayquaza never interacts with characters from its own series.