Final Smash

The Final Smash is a special move that is only possible through the aid of a Smash Ball in Super Smash Bros. Brawl and Super Smash Bros. for Nintendo 3DS / Wii U. After breaking open one of these items, its power flows into the fighter, charging him or her up. The fighter's eyes glow white and yellow, at which point the fighter is free to unleash the Final Smash at any moment by pressing the special move button. However, if the fighter does not initiate the Final Smash soon enough, other fighters can take away the Smash Ball by hitting the fighter in possession of it with a powerful attack. When this happens, the fighter's aura reverts to Smash Ball form and can be claimed by other fighters. Each person's attack is a manifestation of their individual personalities or unique abilities. For example, Zero Laser charges up Samus's Power Suit while Peach Blossom is a magnification of Peach's joyful personality.

The game also has a function known as a Pity Final Smash. The Pity Final Smash can be granted to fighters in special circumstances during a stock match. When the fighter is KO'd while being five stocks behind the leading player, the fighter respawns with a Pity Final Smash. A Pity Final Smash serves the same functions as a normal smash, but it has the advantage of not having a Smash Ball form, and therefore cannot be taken away by other fighters.

Final Smashes are phenomenally powerful and can completely tip the scale of battles. However, each is not without its own repercussions. The attacks can cause self-destructs, and Samus even changes into Zero Suit Samus after using her Final Smash.

Due to the extreme power of the Final Smash, they are usually banned in official tournaments, along with Meta Knight and items.

Final Smash types
While Final Smashes tend to be unique among characters, there are certain categories they can be sorted into.
 * Directional - These Final Smashes launch an attack in a single direction. Depending on the Final Smash, the direction can be controlled, while others are fixed. This kind of Final Smash has a blind spot, usually behind the attacker, where targets can hide. Examples for this kind are Lucario's Aura Storm, Ganondorf's Beast Ganon, and Pokémon Trainer's Triple Finish.
 * Focused - These Final Smashes affect nearby opponents in any direction. Targets can avoid the move by getting out of range, so they're mostly effective in smaller stages. Examples for this kind are Luigi's Negative Zone, Donkey Kong's Konga Beat, Jigglypuff's Puff Up, and Zero Suit Samus's Power Suit Samus.
 * Trapping - These Final Smashes attack a certain area, grab anyone inside said area (or just a single character), and lay down an inescapable beating. They generally have a small initial range and will fail if there are no targets caught. Examples for this kind are Link's Triforce Slash, Meta Knight's Galaxia Darkness, Ike's Great Aether, and Captain Falcon's Blue Falcon.
 * Stage-Wide - These Final Smashes affect the whole stage, leaving little or no hiding spots. However, they may be less effective on larger stages. Examples for this kind are Solid Snake's Grenade Launcher, Pit's Palutena's Army, and Captain Olimar's End of Day.
 * Transformation - These Final Smashes only affect the user, who can then rampage around and cause damage. Some transformations buff up the character's existing moveset, while others use a different set of controls. Most transformations leave the user immune to damage and most status effects. Examples for this kind are Sonic's Super Sonic, Bowser's Giga Bowser, and Mr. Game & Watch's Octopus.

History
Final Smashes are either based on the character's individual background in their series, like Zelda's and Sheik's Light Arrow. However, some may have been invented specially for Super Smash Bros. Brawl, like Mario's Mario Finale. Although they were already planned to be included in the original Super Smash Bros., Final Smashes made their first appearance in Super Smash Bros. Brawl and gained considerable attention due to their ability to turn the tide of battle in seconds. Masahiro Sakurai compared the moves to the Hammer item found in all Super Smash Bros. titles, as all players rush to collect it, and the ones who didn't flee after it has been collected.

Super Smash Bros. for Nintendo 3DS / Wii U
Note: Names in quotations are Japanese names; English names not known yet.