A sacrificial KO (also called a Kamikaze or a Suicide KO) is a maneuver in all three installments of the Super Smash Bros series where one character KOs both him or herself and an opponent with a single move. In most cases, this involves grabbing the opponent and dragging them downwards to the bottom blast line, though self-damaging attacks can also prove effective. Most sacrificial KO's result in the user self destructing.
Sacrificial KOs are useful if the user has a high percentage and the opponent has a low percentage; as the user is likely to be KO'd soon anyway, taking down a comparatively fresh opponent at the same time can even out the match. If the user has a lead in stocks, sacrificial KOs accelerate the match and can even score victories if the victim only has one stock remaining. In the same way, low-damage or trailing players should avoid using sacrificial KOs, as this simply brings them closer to losing. If both players have only one stock remaining, then the user can win, lose, or enter Sudden Death, depending on the exact characterisics of the individual technique.
Sacrifical KOs are typically named by combining the suffix "-cide" with the first part of the character's name.
 Grab-based sacrificial KOs
|All characters||By grabbing an opponent while standing on a piece of terrain that's falling, if the grab is not broken, both characters will be KO'd once the platform reaches the blast line. Stages where this can happen include SSB's Mushroom Kingdom, Great Bay (on the turtle), and any Stage Builder stage that has falling platforms that have nothing below them.||Sudden Death always occurs.|
|Bowser (SSBM)||"Bowsercide" is executed by grabbing an airborne opponent with the Koopa Klaw and falling to the blast line with them in hand. Not exceptionally useful; the move can be escaped, and Bowser is unlikely to recover if the opponent does so.|
|Bowser (SSBB)||"Bowsercide" is executed with the Flying Slam, with Bowser grabbing the opponent and diving off the side of the stage. The move cannot be escaped, but as the lower-damage player has more control over the pair's flight, it's not very useful for evening out percentages.||In PAL and Sudden Death, Bowser always wins. In NTSC, port priority determines whether Bowser wins or Sudden Death occurs.|
|Diddy Kong||"Diddycide" is done by using the Monkey Flip on an airborne opponent and letting the pair fall to the blast line. As Diddy jumping during the grab will meteor smash the opponent, this is rarely seen through to Diddy's demise; he will simply wait until the opponent is low before jumping away.||Diddy always wins.|
|Donkey Kong||"Kongocide" is executed with DK's forward throw, carrying himself and his victim off the stage. This is typically not used as a straight sacrificial KO; it is almost always more useful to throw the opponent under the stage for a stage spike, as the opponent can break free and leave DK's poor vertical recovery to failure.||DK always loses.|
|Ganondorf (SSBB)||"Ganoncide" is done by using the Flame Choke on an opponent with both characters in the air, causing both to plummet downwards. Fast-acting once it connects and inescapable, but very risky to use, as the move causes helplessness if it misses.||Somewhat unpredictable; can either be a loss for Ganondorf or a Sudden Death. It is theorized this has to do with how the upside-down victim's physics bones are located in relation to the right-side up Ganondorf's during their plunge.|
|Ike||On certain stages (such as custom stages), the usage of Great Aether results in the move's diving conclusion falling through a hole and KO'ing all participants.||Sudden Death always occurs.|
|King Dedede||"Dededecide" is executed by inhaling an enemy and walking off-stage. Dedede can easily recover should the opponent escape, but simply spitting the victim underneath the stage is generally more effective.||Sudden Death always occurs.|
|Kirby||"Kirbycide"s are the most famous form of sacrificial KO. Using Inhale on enemies and walking off-stage (or inhaling them in mid-air, in SSB) is highly effective, and in Melee, Kirby can even survive after larger opponents are KO'd out of his stomach. Kirby can also use his forward, back, and up throws as Kirbycides in Melee, though the former two can be escaped (leaving Kirby to simply self-destruct), and the latter one is difficult to execute. Kirby can also use the sacrificial KOs of Dedede and Wario.||Inhale: Kirby always wins in Melee (very small opponents can force Sudden Death); almost always Sudden Death in Brawl|
Forward/Back throws: Kirby always wins
Up throw: Kirby always loses (port priority in Brawl)
|Meta Knight||"Metacide" is executed by using Meta Knight's up throw when against an edge and under a solid ceiling, possibly causing him and his victim to fall off the stage (possibly influenced by the user's movement).||Port priority decides game.|
|Wario||"Wariocide" occurs when Wario uses Chomp while falling, taking his opponent down with him. Difficult to escape but not very popular.||Wario always loses.|
 Other sacrificial KOs
|All characters||The usage of self-damaging explosives is a common (if often unintentional) form of sacrificial KOs. Link and Snake can use their bombs to blow themselves up along with their opponents (though Link's bombs require extreme damages), while Motion-Sensor Bombs, Bob-ombs, Gooey Bombs, Electrodes, and other explosives can be used by anyone.|
|Olimar||On certain stages (such as custom stages), the usage of End Of Day will cause Olimar's ship to fall through a hole and KO him. Unless an opponent gets nailed by the meteor smash of the ship's first appearance, this is extremely unlikely to not result in a net loss for Olimar.|
- Risky meteor smashes or off-stage aerials generally do not count as sacrificial KOs; the term implies that it is the move that KOs the user, not the fact that the user could not recover after using the move.
- Using a move that KOs an opponent in addition to one's teammate (or one's partner Ice Climber) can be considered a sacrificial KO in some ways, with the main difference being that it is not self-sacrificial.
- Sometimes, Olimar's Pikmin-based attacks will require him to throw a Pikmin off the ledge in order to land a KO. In this case, the loss for Olimar is not equivalent to a stock, and it is generally not considered a sacrificial KO, though it involves a level of "sacrifice".