In Stadium, the user becomes uncontrollable during its next turn. Otherwise, the user attacks on turn one but it doesn't recharge on turn two if it KOs the target, breaks its Substitute or misses entirely.
Other Options: Body Slam, Counter, Reflect, Bubblebeam if you're really afraid of Ground/Rocks.
Verdict: You're cool, Wigglytuff. Unfortunately, in RBY, you're also pretty pathetic. Since Wigglytuff's Special stat is all kinds of horrible, she can't really use most of the Special tricks she picks up; in fact, Blizzard is only recommended in case a Rock Pokemon comes out to wall you; Bubblebeam is the same, only less useful since it's only really good against the likes of Rhydon and Golem. Anyway, this set is simple: paralyze something, wear it down with Seismic Toss or Body Slam, and finish it off with Hyper Beam. Sadly, this is the best set she has. :(