Regigigas isn't correct. Ubers can be used in Wi-fi battles, as long as it is agreed upon by both battlers. Also, you won't be using in-game teams for wifi battling. Trust me, you just won't. And, for the love of God, don't use a Spiritomb. Gengar is soo much better with the right moveset. Ick, Spiritomb. Just because it isn't weak to anything doesn't mean it's automatically a good poke.