I agree that it'd be the ??? type too, but what about W/Rs, all neutral ? as for the SkyArceus with Roost hack, that'd be interesting if someone hacked and tried this, to see the W/Rs.I once brought up Roost as a reason for why Chatot was changed from pure Flying to Normal/Flying, but now I'm not so sure. All single type Pokemon technically have a second type, which has no weaknesses or resistances. This may as well be the ??? type for argument's sake. If this pure Flying type were to lose the Flying type for a turn, it wouldn't suddenly crash the game, it would just have this ??? type. In terms of flavor though, it doesn't make much sense for a Pokemon to suddenly have no type, not even Normal.
On that note, somebody hack up a Sky Arceus with Roost and see what happens.
How about a rod those things in photos sometimes they might be a pure flying type.
On that note, somebody hack up a Sky Arceus with Roost and see what happens.