It doesn't even look pokemon-ish even as the official art, Bodine. It is the god of the pokemon world, after all. Also, the thing is, Arceus doesn't have official art yet.. or atleast I don't think so. It was just now revealed, so if official art is out there, it's rare. Either way, here's it's in-game sprite in Diamond/Pearl(it changes in Platinum).
Nick, don't you know? Bar a few ghost pokes like Banette that was created from an "evil", lonesome doll possessed by a spirit, ghost pokemon were previously actual living pokemon. It's ironic ghosts are hard to find, considering there'd be more ghost pokemon than living pokes.