Final Smash

The Final Smash is a secret skill that can be performed but once…and only after obtaining an item called the Smash Ball, which is a precious item, indeed. A Final Smash (最後の切りふだ Saigo no Kirifuda, roughly "The Final Trump Card" or Last Resort) is a Special Move introduced in Super Smash Bros. Brawl and which also appears in Super Smash Bros. for Nintendo 3DS and Wii U and Super Smash Bros. Ultimate.

Overview
Final Smashes are incredibly powerful in comparison to most other attacks, generally leaving the user invincible for the move's duration, and, if properly executed, usually have the capacity to KO at least one opponent. Final Smashes performed correctly will give a great advantage, and may help to catch up to others in the game, or vice versa.

To perform a Final Smash, a player must either destroy a Smash Ball or acquire a "Pity Final Smash". Upon the destruction of the Smash Ball, the character will be engulfed in a multi-colored aura. If too much damage is taken, the Smash Ball will fly out of the character, giving their opponents another opportunity to gain a Final Smash. To perform a Final Smash, simply press the Special Move Button. Multiple Smash Balls can't appear in a match at the same time, but another can reappear after the Final Smash is finished.

Some Final Smashes temporarily slow down stage elements, such as platform movement or motion within the background.

It was revealed in an interview with Nintendo's president, Satoru Iwata, that Masahiro Sakurai had intended for Final Smashes to be included in the original Super Smash Bros., and claims that he has proof, in that there were recorded voices for when characters used their Final Smash. The idea, however, was held off until Brawl.

Pity Final Smash
A Pity Final Smash occurs when a player is KO'd and is 5 points behind compared to the current leader (thereby allowing the player in 2nd place to earn one, provided the gap is large enough). This player respawns with the ability to perform a Final Smash. This Final Smash cannot be dropped by the player. Pity Final Smashes can be disabled only by turning Final Smashes off completely; setting overall item frequency to 'None' alone will not be enough.

Types
While Final Smashes tend to be unique among characters, there are certain categories they can be sorted into. They are:
 * 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. An example of this is the Mario Finale, Mario's Final Smash.
 * 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. An example of this is Puff Up, Jigglypuff's Final Smash.
 * 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. An example of this is Triforce Slash, Toon Link's Final Smash.
 * Stage-Wide - These Final Smashes affect the whole stage, leaving little or no hiding spots. However, they may be less effective on larger stages. An example of this is PK Starstorm, Ness's Final Smash.
 * 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. The transformation is unaffected by all status effects except slow time. It is generally up to the player themselves to deal massive damage with the Final Smash, or else the entire move will be ineffective. An example of this is the Landmaster, Fox, Falco and Wolf's Final Smash. This category of final smash has been discontinued in Super Smash Bros. Ultimate, and all Transformation Final Smashes were turned into Trapping, Stage-Wide, or Directional Final Smashes. Examples of these are Wario, Sonic, and Mr. Game & Watch, respectively.

In Super Smash Bros. Brawl
Out of the 37 Final Smashes in Brawl, 11 are Transformation, 6 are Trapping, 5 are Focused, 8 are Directional, and 7 are Stage-Wide.

Trivia

 * Some Final Smash glitches involve the regenerating portion of the Bridge of Eldin stage, like R.O.B.'s Infinite Final Smash, and Jigglypuff's Giga-Jiggly glitch.
 * In Super Smash Bros. Brawl, if a player is knocked down to 0 HP during a stamina match while in a transformation Final Smash, then they will not technically die and lay there as a "corpse" if there are at least 2 "alive" characters in the game.
 * Under the circumstances that a player is reduced to 0 HP while using a transformation Final Smash in a stamina battle, the player will revert to normal form. Despite being at 0 HP, the player can still move their character and play normally until they are hit another time, which then KO's their character. The glitch is only known to occur in Super Smash Bros. for Wii U.
 * In Super Smash Bros. Ultimate, lightning effects will occur on the HUD upon grabbing a Smash Ball.