Super Sonic
Super Sonic is an in-game form of the video game character Sonic the Hedgehog, first introduced in Sonic the Hedgehog 2. In Super Sonic form, Sonic is faster, tougher, and near-invincible. To reach this form, Sonic must first collect all of the Chaos Emeralds, and harness their power with gold rings.

Overview
Sonic began as a video game on the Sega Genesis console, and later became an animated series. In many versions of the game and television cartoon series, Sonic's main objective is to collect all of the Chaos Emeralds to prevent the evil Dr. Eggman from harnessing their energy to destroy or conquer the world. In the early Sega Genesis original title Sonic the Hedgehog, there were 6 chaos emeralds, all of which are different colors; this number was later increased to 7. In some versions, there is a 'Master Emerald' which contains great energy and can power entire doomsday devices on its own. These Chaos Emeralds are what provide the energy for Sonic to become Super Sonic.
Sonic collects the Chaos Emeralds by entering special stages in which he must collect golden rings or blue spheres (in the first game, Sonic does not need to do this; he must merely break through the walls of the dimension and reach the Emerald without touching the misleadingly-named "Goals"). Once the player has accomplished entering and finishing the special stage seven times, he must collect 50 rings in the real world and jump (double-jump in later versions) to activate the temporary power called Super Sonic.
Since Sonic Adventure, the Chaos Emeralds are mostly obtained through Story Mode, and Super Sonic has only been playable against the final bosses.
Abilities of Super Sonic
Sonic the Hedgehog possesses the ability to run very fast, jump into a spiked ball to attack, perform "spin-dashes", and (in later versions) perform a "super-spin" to rev-up for a spin-dash (see Sonic the Hedgehog). Becoming Super Sonic enhances Sonic's abilities in many ways:
Sonic is invincible
In the Sonic games, to be "invincible" is a temporary condition which means that Sonic is, for the duration of the invincibility, immune to the attacks of enemy "badniks" (Robotnik's robotic creations). It also allows Sonic to destroy most badniks by simply touching them ("bosses" like Robotnik himself always take multiple hits to defeat, but they too can be damaged by simply bumping into them). Sonic is still susceptible to death by anything that causes death without ring loss, such as drowning, being crushed, or falling to his death. Normally, Sonic is never invincible except when he picks up the temporary Invincibility Box.

Sonic's abilities are enhanced
Which is to say that all of Super Sonic's movements, including running, spin-dash, jumping through the air, flying, climbing walls (with a rope), etc. are sped up to the max. This often means a total inability for the beginner to control Sonic's movements due to his flying through the air so fast and often getting himself killed by leaping off cliffs by mistake. Luckily, this is countered by an increase in Sonic's agility: Super Sonic can easily switch directions or stop himself, especially in the air. Sonic also jumps much higher and remains in the air for an abnormally long time (allowing for the flying-off-cliffs incidents).
Also, especially in Sonic 2, the camera occasionaly has problems keeping track of Sonic, so much that Sonic occasionally dies for no apparent reason after the camera is forced to play catch-up.
Super Sonic can also fly, he only did this in Doomsday Zone in Sonic & Knuckles in the 2D games, but since he now only fights final bosses in the air or in space, Super Sonic always flies.
Hyper Sonic

Hyper Sonic has only appeared in Sonic 3 & Knuckles. He glows with the c
olors of the Chaos Emeralds, is surrounded by flashing sparks and leaves afterimages in his wake. His abilities are the same as Super Sonic's, though he can breathe underwater and has the added ability of a devastating lightning "HYPER FLASH" attack, which fans like to call the Sonic boom. This can be used to 'double-jump' in any direction and when performed, destroys all enemies on-screen, except bosses, with a bright flash. Unlike the game's Lightning and Flame Shield, the player may choose the direction of Hyper Sonic's second jump by holding a direction on the D-pad.
Appearances
Super Sonic can also be found in: Sonic the Hedgehog 2, Sonic the Hedgehog 3, Sonic & Knuckles, Sonic the Fighters, Sonic Jam, Sonic R, Sonic Pocket Adventure, Sonic Advance, Sonic Advance 2, Sonic Advance 3, Sonic Rush and Sonic the Hedgehog 2006.