Rayquaza

Rayquaza (レックウザ Rayquaza) is a /-type Legendary Pokémon.

Rayquaza is the version mascot for the game Gameboy Advance game Pokémon Emerald.

Anime
Rayquaza appears in the 7th movie, Destiny Deoxys. It just flies down from the ozone layer, blasting out Hyper Beam's to "help" the world against Deoxys, who was trying to find its brother, who was still a green crystal trying to be revived by a couple of scientists, and soon, Ash and co. Deoxys however causes a lot of trouble. It can't tell if Rayquaza is trying to help the world or destroy it. Same with the world, so it attacks anyone in its way. Deoxys has the power to regenerate in the movie, which let it regenerate after Rayquaza let out a major Hyper Beam up close and obliterated it. Also, it could create clones of itself to search the city.

Games
Rayquaza is a Generation III Pokémon, first appearing in the Pokémon Ruby and Sapphire games. In 2004, Rayquaza became the version mascot for the Pokémon Emerald game.

In Hoenn region mythology, it was said to stop the fighting between Groudon and Kyogre. Rayquaza in Ruby, Sapphire, and Emerald can be found at the Sky Pillar. It lives in the ozone layer far above the clouds and cannot be seen from the ground. It is noted for protecting its territory fiercely.

Rayquaza is Level 70 if you face it in Pokémon Ruby/Sapphire/Emerald, it has a starting moves of Extremespeed, Outrage, Rest and Fly.

Super Smash Bros. Brawl
Rayquaza is the second main boss you have to fight in Super Smash Bros. Brawl. You fight it as Fox or Diddy Kong in the Subspace Emissary.