Self-destruct

A self-destruct, often abbreviated SD, refers to a player getting KO'd without being hit by opponents, whether by jumping off stage and failing to reach it back, getting KO'd by stage hazards, defeating a teammate when team damage is turned on or backfiring with the player's own item. In time, self-destruct subtracts one point from the player's current score.

Super Smash Flash includes two bonuses: "SDs bonus" which penalyzes -500 points for every self-destruct the player commits, and "Self-Destructor bonus", which penalyzes -2000 when player has a lot of self-destructs.