Rhythm Twister

Rhythm Badge is Tails' side attack in Super Smash Flash and side special move in Super Smash Flash 2. Tails spins around while using his tails as a whip. If you continue to hold the special attack button and the arrow keys, you can move forever. You can also jump doing this.

The rhythm badge is actually an item Tails obtained in Sonic Adventure that allowed him to kick with his tails forever. It was necessary to advance in the story, but not exactly necessary in gameplay.