From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Fox_Illusion&oldid=2360780"
Fox Illusion is Fox's side special move introduced in Super Smash Bros. Melee. Fox suddenly dashes forward at a high speed, damaging any opponents in his path with an after-image. In Super Smash Bros. Melee and Super Smash Bros. Brawl Fox is left in a helpless state after using it in midair, though the move can be stopped by pressing the special move button again; in Super Smash Bros. for Nintendo 3DS / Wii U this no longer occurs, and Fox automatically stops moving at the end of a ledge if used on the ground, and can no longer be stopped mid-attack.
In Super Smash Bros. for Nintendo 3DS / Wii U this move has two custom variations. The first variant is Fox Burst, which no longer deals damage during the attack but creates an explosion at the stopping point that deals greater damage and knockback. The second is Wolf Flash, which behaves similarly to Wolf's move in Super Smash Bros. Brawl; it does not travel as far but gives Fox some vertical distance as well as a sweetspot at the end of the move that behaves as a meteor smash.