Wobbuffet

GSC is a stalling environment, a lot of people will agree with that. With Wobbuffet's stats and moves, you'd think that it'd be a great tank to use on a stall team. However, Wobbuffet doesn't learn any healing moves. So the only way it can recover HP is if Wobbuffet is passed to a Pokemon who is under the effects of Leech Seed. Even then, that Pokemon has to be trapped by Mean Look or Spider Web. If your opponent's Pokemon is not trapped, then Wobbuffet's major flaw kicks in. As long as your opponent has two Pokemon, he or she can continually switch them out between each other. This stalls, yes, but it renders Wobbuffet useless. This applies especially if Wobbuffet is your last Pokemon.