Sonic the Hedgehog protagonist Sonic the Hedgehog, a blue hedgehog able to run at supersonic speeds, and recurring villain Dr. Eggman, an evil scientist whose ambition is to conquer the world. Among Sonic's many allies, the most well-known include: Miles "Tails" Prower, a twin-tailed, highly intelligent yellow fox who is Sonic's sidekick and best friend; Amy Rose, a pink hedgehog who is Sonic's self-proclaimed girlfriend and a hero in her own right; Knuckles the Echidna, a coolheaded red echidna who is the guardian of the Master Emerald; Shadow the Hedgehog, an anti-heroic doppelgänger of Sonic with a dark past; and Metal Sonic, a
Sonic the Hedgehog Since Emeralds of the 8-bit version of "Sonic the Hedgehog" were hidden in the main stages, the game's spring-filled Special Stages were merely used as a means of adding variety, increasing score and earning continues. Similarly, "Sonic 3 & Knuckles", in addition to the main Special Stages, featured entirely optional bonus stages, one of which combined the rotating maze of "Sonic the Hedgehog" with the pinball gambling of "Sonic the Hedgehog 2". "Sonic Heroes" contained an alternate Special Stage for a chance of earning additional lives. A super transformation is a state certain characters go into that gives them incredible