Character: darkspine sonic
Darkspine Sonic, or just Darkspine, is an alternate form used by Sonic the Hedgehog exclusively in Sonic and the Secret Rings, released exclsively for the Nintendo Wii in 2007.
Sonic assumes this form towards the end of the game when the main antagonist, Erazor Djinn manipulates Shahra Genie of the Ring into giving him the 7 World Rings and sacrificing Sonic to gain the power to take over the world. However, Sonic tried to stop her by wishing with her ring to, "Do what you truly think is right!" , resulting in her sacrificing herself instead so that the rings can be used by Sonic. Erazor absorbs 4 of the rings (Prayers, Joy, Pleasure, and Wishes) and transforms into Alf Layla wa-Layla. Sonic absorbs the remaining 3 (Sadness, Rage, and Hatred) to become Darkspine Sonic. Both forms are immensely powerful, but since neither of them have all 7 World Rings, they are both considered incomplete.
In this form, Sonic's fur and arms become a deep indigo color, and his skin turns pale white. He also gains a single, thick white stripe around his feet, and around his arms (close to where his elbows are), as well as a pair of much thinner white stripes that go up his forehead and down his upper middle quill, and a secondary pair of stripes on his lower middle quill. In addition, Sonic's pupils and irises disappear entirely. His eyes also become slightly more angular in shape, and his quills hang lower than usual. In terms of attire, Sonic loses his trademark gloves and shoes and instead gains four glowing golden rings around his wrists and ankles. His voice also undergoes a slight change: becoming much gruffer, but maintaining its normal pitch. He is also constantly enveloped in a large, flaming, orange aura.
It is the only time in the main series of Video Games where Sonic does not wear shoes or gloves.