Stamina is a Special mode option in all games where Special mode is present, that replaces the Smash Bros.-centric damage percentage with a "life bar" similar to that of conventional fighting games, which must be depleted to defeat characters. The mode also appears to an extent as a possible Smash Run Final Battle in Super Smash Bros. for Nintendo 3DS.
In Stamina, every hit to the player depletes some HP from them. Once a character reaches 0 HP, they are out of the game, though characters can still be knocked off the stage through conventional means. However, knockback is not affected by the amount of damage the player has taken. When the character reaches 0 HP, the game will temporarily slow down, and the character's Star KO scream will play; this does not apply to Super Smash Bros. for Wii U as they would slowly get knocked out without any noise, but in Super Smash Bros. for Nintendo 3DS they might have their Star KO scream played. If trapped in a Final Smash such as Ike's Great Aether, then the character will be "dropped out" from the move. Afterward, the character will always stay in their lying down position, and will always enter a state of tumbling when hit; as a cosmetic change, the character flashes red. Any "drone" characters, such as Pikmin, however, will still stay next to the knocked out combatant, except for Luma, who will be KO'd alongside Rosalina.
In Melee, the starting stamina is fixed to 150 HP. Brawl introduced the ability for players to select their starting HP individually via the Handicap option, allowing all tens from 10 HP to 300 HP, as well as only 1 HP. In Super Smash Bros. for Wii U, Stamina returns as a Special Smash option, but the 1 HP option is removed.
Healing items and moves cannot heal a player's HP past their starting amount.
Mechanically, characters are considered to have a negative damage percentage while they have positive HP, which is why they take little knockback until KO'd, at which point they begin to take more knockback as damage rises as expected.
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