Super Smash Bros. Melee/Pikachu

Note: Pichu has these same attacks, only weaker (for example, its Quick Attack doesn't do damage) and they hurt Pichu.

Thunda Shocker
A good stragedy with Pikachu is to just use thunder repeatedly. your opponent will then be to scared to come near you so just use a few thunderbolts until they attack. If they have long-ranged attacks and are not coming near you can simply jump above them and use thunder.