Deoxys, Pokémon #386 and star of the Upcoming Pokémon Movie. This Pokémon is also the ONLY Pokémon to Have Different Sprites throughout the Different games. Above is his Ruby/Sapphire sprite and here are the others:

Fire Red	Leaf Green

So that proves Deoxys is a Shapeshifter, and he is found on Island 9 - Tri Island