Rayquaza

Rayquaza is a legendary Pokémon in the Pokémon series. It is known as a sky god in the games and the main Pokémon of Pokémon Emerald. It makes its Mario series debut in Super Smash Bros. Brawl. It appears out of a lake in the jungle when its hears Diddy Kong. It attacks him with what is presumably Dragon Pulse, and snatches him in its hand. Afterwards, Diddy Kong screams for help and Fox then comes out of his Arwing (which Diddy found earlier). Rayquaza and Fox then duke it out with Fox being the victor and Diddy Kong being saved. Rayquaza sinks into the lake. If it will be in the game later or if it will be a boss like Petey Piranha is unknown.

Trivia

 * Rayquaza is a portmanteau of Ray and Quazar.