Skull Bash
Skull Bash is Pikachu and Pichu's Smash B move in Super Smash Bros. Melee. It is similar to Luigi's Green Missile, only without the chance of a misfire. The move can be charged up to increase the damage and range of the attack. Pichu can charge for longer, but hurts himself upon releasing; the knockback when fully charged is tremendous, and is used in most Home Run Contest strategies in lieu of the bat. In Brawl, Skull Bash charges much faster than in Melee, and is an excellent move to recover with. When fully charged Pikachu will go about as far as the size of Final Destination.
Skull Bash is based on a move with the same name in the Pokémon video games. The Pokémon that uses it first must spend one turn getting ready for the attack, then launches itself at its opponent the next turn. Strangely, Pikachu are no longer able to learn Skull Bash in the Pokémon games, while previously it could only learn it from a TM in Generation 1.