Super Knuckles
From Sonic Retro
Template:SuperCharacterSheet Knuckles has the ability to power up using the Chaos Emeralds. When he does this, he becomes Super Knuckles. Like Super Sonic, Knuckles' super transformation confers the traditional effects of a Super State which include higher speed and invincibility. Character specific traits include improved gliding and climbing. The echidna's hue change isn't as radical as Super Sonic's; he simply glows and trails flashing stars.
Along with Tails, Knuckles was given a new Super State in Sonic Heroes, thanks to Chaos Energy from Super Sonic. While the only physical change was a golden spherical aura (similar to Super Sonic's in Sonic Adventure), Knuckles received all of the modern abilities of a Super State. These include the ability to fly as well as the inability to brake. Additionally, Knuckles received a powerful attack where he could create explosions by simply punching and the ability to use an attack similar to his "Maximum Heat" attack of Sonic Adventure. Fans were upset that this state didn't take on the original appearance of Super Knuckles and because of it, there is doubt in the minds of some that it is a Super State at all.
In the Archie-published Sonic the Hedgehog comics, Knuckles can use 7 Chaos Emeralds or the Master Emerald to turn into Hyper Knuckles. In this state, Knuckles's fur turns pink, and his eyes turn red. Knuckles was also able to turn into a green-colored Chaos Knuckles. This was Knuckles' most powerful form, but he lost this power when he came back from death. In this form, Knuckles was the most powerful Chaos entity of Mobius (second only to Chaos, who was currently enshrined in the black emerald).
In Sonic the Hedgehog issue 141, "Hyper Knuckles" was misprinted as "Super Knuckles".