Arceus

Arceus is a Pokémon that appears in the Mystery Dungeon series.

Biography
Arceus is known as the god of the Pokémon world, as he was born before the existence of Pokémon itself. He can change his type depending on the plate he holds.

Super Mystery Dungeon
After getting all other 719 Pokémon connected, you shall get a request to met him at Destiny Tower on floor 99F. Accept it, and reach there in order to interact with him.