Super Ix is a transformation of Imperator Ix, leader of the Nocturnus Clan echidnas. He is faced as the final boss in Sonic Chronicles: The Dark Brotherhood.
After Knuckles' party and Sonic's party fight a total of three battles against the Imperator and his Power Throne, the arch-villain casts aside his voluminous raiment and transforms. The precise nature Ix's transformation is a bit hazy; with both the Master Emerald and the Chaos Emeralds in close proximity, it could be a typical 7-Emeralds super transformation, or a more novel form like Super Mecha Sonic's. Ix claims he's "summoning the power of the Nocturne itself" to transform, while Sonic proclaims "If he's using the power of the Emeralds, so can I!" before turning into Super Sonic to fight the boss.
Both Super Sonic and Ix have a HP quantity of 10,000, or as the game says; "???", likely meaning that thier health is uncalculable. Both of their attacks are unreasonably overpowered.
Imperator Ix's only technique is an incredibly intricate POW move called Overload, which somewhat resembles his normal form's Dark Anomaly attack. Super Ix goes down in a single round if you use Super Sonic flawlessly. After Super Sonic defeats him, Ix teleports away as the wormhole back to Sonic's world closes.