Super Smash Bros series
Thunder is a move that Pikachu can perform in the Super Smash Bros. series. In the Super Smash Bros. series, the move would bring a bolt of lightning down from above, damaging any opponent above you. Pichu can also use Thunder in Super Smash Bros. Melee. It's Thunder move was slightly different, as it would harm the Pokémon if it touched it, while this wasn't the case with its evolved form.
In Generation I
Thunder deals damage and has a 10% chance of paralyzing the target. Thunder cannot paralyze Electric-type Pokémon.
By leveling up