Bankai Ichigo

Bankai Ichigo, also known simply as Bankai, was originally 's Final Smash in Super Smash Flash 2 prior to Beta 1.2, where it was replaced by Mugetsu.

Overview
When performed, Ichigo would concentrate his spiritual energy and envelop himself in a dark, massive whirlwind-like explosion that deals 25% damage and high knockback to opponents hit. When it would disappear, his Zanpakutō would be transformed into Tensa Zangetsu and Ichigo himself would be temporarily transformed into his Bankai form. Bankai Ichigo was one of the many "Final Forms" in the game, which means he was much different from his normal form and had greatly improved attributes, such as more powerful attacks and increased knockback resistance.

As a Final Form, Bankai Ichigo excelled in his speed, possessing one of the fastest dashes in the game. Bankai Ichigo also had a floating ability and could midair jump infinitely. This, coupled with his good aerial attacks, made him a less "slippery" character when it came to controlling him in the air or jumping. He had two aerials, and forward, that would meteor smash and semi-spike opponents without any need of a sweet spot. However, his aerial attacks had a long start-up lag.

Origin
In the  franchise, Bankai is the second and final form of a Zanpakutō. Only the strongest Shinigami can use it, and it is the ultimate technique of a Zanpakutō. To achieve this form, one must be able to materialize and subjugate their Zanpakutō spirit, meaning the wielder needs to summon it into the physical world. It usually takes ten years or more to achieve, plus the experience needed to master it, but Ichigo was able to achieve it in just three days with Yoruichi's training. The training program involved using a Tenshintai, which forcibly materializes the spirit of a Zanpakutō into the Human World when stabbed by the Zanpakutō, effectively bypassing a large portion of the training and significantly reducing the amount of time needed to complete it. This device was invented and tested by Kisuke Urahara, the only other person who attained Bankai through the same method that Ichigo would eventually use. The power and forms of Bankai vary according to the wielder's strength and training, but in general, one's power can grow five to ten times greater by attaining it. Because Ichigo is a very special Shinigami, Bankai power multipliers could be much larger.

Trivia

 * Inside the data files of Super Smash Flash 2, there is an unused icon of Bankai Ichigo for Classic mode. He shares this trait with Wario-Man, Super Saiyan Goku, Kyūbi Naruto, and Crazy Hand.
 * When hit with a flame attack, Bankai Ichigo would be completely enveloped in a giant ember instead of just letting off puffs of fire or smoke.
 * Prior v0.2a of the SSF2 Demo, Bankai Ichigo used an uncharged form of Kuroi Getsuga as his down special move rather than Multislash.