Knee Smash

From SmashWiki, the Super Smash Bros. wiki

Not to be confused with the first hit of Solid Snake's forward tilt, which can be used to perform the Knee Lock.

The Knee Smash, also known as the Knee of Justice or simply the knee, is Captain Falcon's forward aerial in Super Smash Bros. Melee and Brawl. It is an extremely powerful, low-trajectory killer often used at the end of Falcon's combos.

This move is considered among the best in the game, due to its short lag time and powerful knockback ability. Most combos and strategies end with a knee, which deals up to 18% in Melee and 19% in Brawl, under circumstances not influenced by items or stage effects.

The Knee Smash has two main hitboxes. The initial hitbox, which lasts only a few frames, is Captain Falcon's primary killer and is accompanied by an electrical pulse. This hitbox is considered the attack's sweet spot. The second hitbox lasts much longer and lacks the damage and knockback of the sweet spot. Due to the Knee Smash's low lag, professional smahers can use it as a launcher into another aerial attack, often a sweet-spotted Knee Smash.

In Brawl, the knee is much harder to land and its knockback power has decreased slightly. Its hitlag lasts about a second, much longer than in Melee.

Though Ganondorf is Captain Falcon's clone, his forward aerial is not a knee but is instead an arcing downward punch resembling Mario's in both Melee and Brawl. However it has the same amount of startup frames as Falcon's Knee.