Mecha Sonic

Mecha Sonic is a powerful robot which serves as the secondary antagonist in the video-game Sonic and Knuckles - although he is often confused with Metal Sonic, he is actually a unique character, much as Silver Sonic is also considered a different Badnik.

Mecha Sonic was the second robotic version of Sonic created by Dr. Eggman (or Dr. Robotnik, as he was called back then), the first being Silver Sonic. Sonic fought him three times at Sky Sanctuary while tracking down the Death Egg. The first time Mecha Sonic was in a pod similar to Eggman's Eggmobile, using a ball and chain. The second battle was similar to a few previous Eggman battles with metallic eggs circling him. The third battle he faced Sonic head on, using jump and dash attacks, but Sonic defeated Mecha Sonic, supposedly killing him.

However, when Knuckles arrived at Sky Sanctuary sometime after the Death Egg was destroyed, Mecha Sonic was revealed to still be alive. Aiming for Knuckles, he destroyed the Egg Robo that took Eggman's place during Knuckles's playthrough and fought Knuckles the same way he fought Sonic in their third battle. Knuckles defeated Mecha Sonic, who absorbed power from the Master Emerald to turn into a super form. Knuckles was still able to defeat Mecha Sonic, completely destroying him.

He was shown in a postcredits scene recovering from damage and absorbing power from the Master Emerald; however, this was likely just a representation of the battle between him and Knuckles, as he was shown to be completely destroyed after the battle and does not appear in any later games, replaced by the more infamous Metal Sonic.

Appearances in other media
Mecha Sonic is the name given to the roboticized version of Sonic the Hedgehog in the Sonic the Hedgehog comic book series by Archies Comics.

Robotnik managed to have Sonic captured by Nack the Weasel and roboticized and took control of Sonic. Mecha Sonic, as he was called, was sent to Knothole, where he managed to defeat both Bunnie Rabbot and Knuckles, and continued to wreak destruction on the village, until the Freedom Fighters were left with only one option. In the Mecha Madness super-special, Knuckles roboticized himself, using a neural overrider to retain his will. Mecha Sonic and Mecha Knuckles fought to a standstill, until they were both sent spiraling towards Robotropolis, where their impact caused a nuclear explosion which severely damaged Mecha Sonic, and would have killed Mecha Knuckles had it not been for Sonic's regaining his will and throwing himself in front of Knuckles at the last minute. Afterward, Nicole managed to de-roboticize Sonic with the help of the magical protection conferred to him by his recently acquired one billionth power ring.

Mecha Sonic was able to fly and hover using thrusters in his shoes. He had hyper jet boosters, teleportation, laser blasts, twin wrist lasers and dramatically increased strength, and his computer brain gave him digital tracking and allowed him to do complex mathematical calculations in seconds. Mecha Sonic stood at 130 cm and weighed 170 kg.

Mecha Sonic reappeared for one issue when Sonic and Tails were robotized by the Bem to fight Dr. Robotnik and Snively (who had been transformed back into organics) in an experiment to determine whether or not organic Mobians were superior to roboticized ones. Sonic and Tails won the battle and were reverted to normal afterwards.

Trivia

 * Technically, Mecha Sonic is the final boss of Sonic & Knuckles, as Knuckles's playthrough is set after Sonic's playthrough, which would make him the first final boss in a Sonic Game aside from Eggman.
 * In the Japanese version, Mecha Sonic and Silver Sonic are treated as the same robot, under the name "Mecha Sonic".
 * In Sonic Adventure, an upgraded Mecha Sonic is seen in one of the tubes in Eggman's base.