Final Smash

The Final Smash attack is a new special move that will be featured in Super Smash Bros. Brawl. The player will only be able to perform this move once. The Final Smash move is triggered by collecting a Smash Ball, which will randomly appear as the battle goes by. The move is an incredibly powerful attack, reaching the power equivelant to the Hammer from Super Smash Bros. Melee. However, there are usually a few backfires to using such a powerful move, like bad accuracy, or bad control. Each character will have his/her very own version of the Final Smash.

Final Smash Moves
http://www.gamepro.com/nintendo/wii/games/previews/139928.shtml