The transformation that Sonic goes through when he receives the seven Chaos emeralds. This Transformation causes him to gain incredible speed and power. Sonic First used this in
Sonic the Hedgehog 2, to defeat Dr. Robotnick.Many believe this to be a copy of the Transformation that a Saiyan goes through in the Anime Series "Dragon ball Z". A few reasons for this are that First of all, Yugi
Naka was a huge DBZ fan. Second, Sonic the Hedgehog was created in 1991, while the Anime of DBZ came out in 1989, and the Manga came out way before that. And finally,
Sonic's Hair, or fur, turns golden, and he becomes more powerful.