100-Man Melee, 100-Man Brawl, 100-Man Smash, and Century Smash are Multi-Man modes in Super Smash Bros. Melee, Super Smash Bros. Brawl, Super Smash Bros. 4 and Super Smash Bros. Ultimate, respectively. They challenge the player to defeat one hundred opponents (Fighting Wire Frames in Melee, Fighting Alloys in Brawl, and Fighting Mii Team in SSB4 and Ultimate) without getting KO'd or Self-destructing. In 100-Man Brawl and 100-Man Smash, playable characters appear as every twenty-fifth opponent. Unlike the regular opponents, these characters are able to take advantage of any items that may appear. This mode usually takes a few minutes for players to defeat.
A certain level of difficulty is programmed into four different checkpoints of 100-Man mode. After beating a certain amount of opponents, their behavior will change and they will gradually become more difficult. The amount at which the opponents are released will also increase. These checkpoints are shown by either a short pause in the spawning of opponents, or by a spike in the amount at which they are spawned.
Beginning (0 opponents defeated)
At the beginning of the match, two to three opponents spawn and they will gradually increase to between four and five. However, they are at a very low level, that of a level 1 Computer Player. There will be a short pause after defeating the first 25.
25 opponents defeated
After 25 opponents are defeated, the amount at which they spawn will reset, but will gradually increase again. They are aggressive and slightly more dangerous than the first 25 foes.
50 opponents defeated
After 50 opponents are defeated, the amount at which they spawn will reach a maximum of between four and five. Most will constantly approach the player, while some may spread out among the stage. This checkpoint is where most players begin to encounter challenges. In Smash 4, the fiftieth foe will be in giant form.
90 opponents defeated
At some point after 90 opponents are defeated, there will be a small pause during the last few foes to acknowledge that the match is nearing its end. Nevertheless, the last few opponents will shield, dodge, and use smash attacks much more often.
99 opponents defeated
Right before the final challenger, there is one last pause. After the short pause following the defeat of 99 opponents, the final foe will spawn. It is much heavier than any of the previous foes, and as a result, is slightly harder to defeat. In Brawl, the last foe is the player's character (always player one if playing co-op). In Smash 4, the last foe will additionally be in giant form. In Ultimate, the last foe will instead be in normal size form.