No KO
A No KO is a type of Custom Stage in Super Smash Bros. Brawl. A No KO is basically a stage in which it is impossible to cause a KO through normal means. No KOs are commonly used to see how much damage a Final Smash can cause. A Stamina Match causes an easy KO, but other means are possible...
Basic Layout
A standard/typical No KO is composed of a square/rectangular area of basic blocks, with spikes along the top to prevent characters from spawning there. Variations include triangular shape to cause a slant for items, hindering item usage as soon as they spawn, a more rounded stage to provide an aiming challenge, made of icy blocks, and a roof of drop blocks.
KOing in a No KO Stage
As the stage type requires at least one space between stagetop and blast line, there are several things that make a KO possible. Several Final Smashes can KO/SD Ike's Great Aether Attack sends Ike and his opponent to the peak of the stage, causing a Star/Screen KO and leaving Ike above. Lucario's Aura Storm sends Lucario himself to the peak, which may cause him to SD. Pikachu's Volt Tackle allows Pikachu to pass through walls/platforms, so if Pikachu is out of the arena when the Final Smash ends, he will SD.
It is also possible to SD using by exiting the stage with a warp star, however, it is possible to survive infinetely on top of the spikes.
A glitch has been dicovered in which if a fighter is damaged repeatedy at the wall of the stage, they will fall through the floor and KO.