Smashdown (全員バトル, Everyone Battle) is a multiplayer mode in Super Smash Bros. Ultimate. It consists of a series of matches, and after a character has been used in a match that character is not able to be chosen again until the series of matches is completed. It is one of three modes in the game's Special Smash mode, the other two being Custom Smash and Super Sudden Death.
Each player chooses a different character and participates in a standard Smash battle. After the battle ends, the characters used disappear from the roster for the rest of the game. Mii Fighters are not available in this mode, and Echo Fighters are always displayed and counted as separate character from their parent, regardless of the player's display settings. Also, the number of battles played before the game ends can be adjusted, and enabling Mercy Rule will cause the game to end if a player has won too many battles for any other players to make a comeback.