Super Knuckles

Super Knuckles (スーパーナックルズ) is the Super Transformation of Knuckles the Echidna that is gained once all seven Chaos Emeralds are collected. The only appearances of Super Knuckles were in Sonic & Knuckles, Sonic 3 & Knuckles, and Knuckles in Sonic 2. This is the one of the only two transformations demonstrated by Knuckles in the Sonic game series, the other being Hyper Knuckles.

Appearance
Super Knuckles has a bright pink pulse to his body and a pink aura around him, but retains his basic physical form, unlike most other super transformations.

Powers and abilities
While in his Super form, Knuckles is granted the traditional invincibility towards any attack. All his physical attributes has as well be enhanced in this form: His strength has been increased greatly, allowing him to plow through any obstacles and his movements has been enhanced as well, vastly increasing his speed, jumping, gliding, climbing, etc. Like every other super transformation caused by the Chaos Emeralds, once he runs out of rings he loses his super form.

Archie Comics
In the Archie Comics, to set up a battle with Super Sonic, Knuckles' super form was dubbed "Hyper Knuckles", to avoid the monotony of two supers against each other.

Knuckles' first known transformation into his super form was when he went head-to-head with Super Sonic in a battle for the Chaos Emeralds, their battle eventually destroying the Zone they resided in. Knuckles later turned into Hyper Knuckles again to battle Master Mogul, along with Super Sonic and Turbo Tails.

Knuckles later obtained his Super Form to fight Hunter on Angel Island using the power of the Master Emerald. In this form, Knuckles looks almost demonic and appears to be in pain when undergoing the transformation. As Super Knuckles, Knuckles was able to stop a spear which sends its victims to the Egg Grapes and proceeded to attack Hunter, picking him up, spinning him around, and throwing him into the ocean where he drowned.

Trivia

 * Super Knuckles, unlike most other super forms, doesn't have a golden glow, but rather a pink one.
 * Super Knuckles was also referenced in Sonic Chronicles: The Dark Brotherhood in the Chaos Emeralds part of the journal, stating that Sonic, Shadow, Knuckles and a variety of people have been known to use the power of the seven Emeralds to go up to powered up versions of themselves.
 * This transformation is similar or even the same as Hyper Knuckles.
 * in Sonic Heros super knuckles was red.