User blog comment:Moonlit Sylveon/Mega Pokémon Ideas -- Which Pokémon deserve a Mega Evolution?/@comment-25073732-20140819205251/@comment-25073732-20140820153813

IF there were a mega porygon-z, the scientists would definitely have made the mega stone for it since a mega stone for a man made pokemon wouldn't exist, since porygon-z hasn't existed long enough for a mega stone for it to form naturally.