Sonic is a slim anthropomorphic hedgehog with blue fur that covers most of his body and peach skin that covers his arms, muzzle and front torso. He had a round head and an equally round torso in his younger years, with black eyes. However, he developed green eyes as he became older. Sonic was also shorter and stubbier, but he has since grown significantly taller and thinner since then. He also has six long quills on the back of his head, two spines protruding from his back behind his shoulders, and a short tail.