Mecha Sonic's Super State

Super Mecha Sonic (a.k.a. Super Metal Sonic) is the super form of Mecha Sonic from Sonic & Knuckles. He is the final boss of the game in Knuckles the Echidna's storyline, and appears in the Sky Sanctuary Zone.

History
Mecha Sonic achieves this "super form" by jumping on top of the Master Emerald and absorbing energy from the Emerald directly into a red power core in his chest. This transformation turns Mecha Sonic into a golden-orange color, and makes it invulnerable to attack. It also gains the ability to hover at the top of the screen for extended periods. However, it is unable to sustain its power for very long and will soon revert to its normal form and attempt to recharge.

In this form, Mecha Sonic attacks by spinning toward Knuckles' current position, firing three charged balls of energy. This seems to be the attack that drains its energy, although other attacks include trying to ram into Knuckles at speed. It can only be damaged whilst powered down. Halfway through the battle however, the attack pattern completely changes and Mecha Sonic hovers at the top of the screen back and forth firing a series of rings. It occasionally loses power for a split second, for unknown reasons, causing it to momentarily drop. This is Knuckles' chance to attack.

If Knuckles has collected all of the Chaos Emeralds (and, if playing Sonic 3 & Knuckles, all of the Super Emeralds), then Super Mecha Sonic is totally destroyed at the end of the boss battle. However, if the Emeralds have not all been collected, Mecha Sonic reappears at the end of the credits, sparking and with glowing red eyes.