If so, could it be transferred?
Arceus is not meant to be legitimately obtainable in its ??? type form. The only reason why a sprite existed for it was as a precaution in case someone hacked their Arceus to force it to be ??? type.
??? isn't meant to be a type for Pokemon, it is only used to make eggs and the move Curse seem mysterious. The ??? type was removed in generation 5 and has not reappeared since.
The ??? Arceus sprite: It is not seen anywhere in the normal game, so you will never see this sprite except through hacks.
Source
No, there is no way to do this w/o hacking.
