- Enhanced super strength
Dark Sonic (ダーク・ソニック, Dāku Sonikku?), also known as Dark Super Sonic, is Sonic's darker and angrier form. His first and only appearance was in the sixty-seventh episode of the TV show Sonic X when Cosmo is scared and Chris is injured by Black Narcissus of the Metarex. The multitude of fake Chaos Emeralds and Sonic's intense anger allowed him to achieve this transformation. While in this state, Sonic shows his fury by destroying the two prototype Metarex that Black Narcissus pits against him (in just a few seconds) in order to test his abilities.
Dark Sonic looks similar to Super Sonic, except he has a bluish-black color, a blue aura, and no pupils or irises when he is at his true power.
Sonic mid-transformation.Added by HeidiHedgefoxWhen Sonic first crashes into the Metarex's base in episode 67, his first comment, after mentioning how many fake emeralds there are, is "Ugh... suddenly I don't feel so great!" in the English version and "Ugh... just looking at them makes me feel sick!" in the Japanese version. These comments are prompted by the negative energy Sonic can feel from the fake emeralds. It is this dark Chaos Energy that incredibly intensifies Sonic's rage at seeing an unconscious Chris and a terrified Cosmo trapped, that causes him to turn into Dark Sonic. Sonic is completely consumed by this combination and he attacks, seeking complete vengeance. He quickly destroys both of the machines the Metarex designed to test Sonic's strength and speed. As Dark Sonic, Sonic seems to take a murderous pleasure in doing so, indicated by his mad cackling and evil grin beforehand. Sonic's powers fade when he is calmed down by Doctor Eggman, who declares he has never seen Sonic so worked up before. Eggman says he does not want to see Sonic act out of anger and rage and how it is not good for him. In the English version, Eggman also says that if Sonic lets his temper get the better of him like this again, he may become angry all the time, "like another certain hedgehog [they] know". This last sentence seems to refer to Shadow the Hedgehog.