When playing as Sonic, start a Spin Dash (side B) while standing on a slope. He must not be on flat ground by the time he is done moving backwards while charging the Spin Dash. An example of this would be on the Hyrule stage (stand on the flat part between the two sets of stairs), or on the Pokemon Stadium stage (when it gets Ground-type themed, start the Spin Dash from the middle of the "ramp"). If done correctly, Sonic will not be able to do the "jump" at the beginning, and will "fly" through the air until either you jump or he hits someone. If he hits a wall while "flying", he will hover for a while, then stop. If he hits someone, he will teleport either back or up then back and will skid (through mid-air) to the place where he hit them.