Hyper Sonic
From Sonic Retro
Hyper Sonic is a form similar to Super Sonic in that it makes Sonic faster, invincible, requires fifty rings and makes Sonic glow.
However, instead of requiring the seven Chaos Emeralds it requires the seven Super Emeralds from Sonic & Knuckles which are obtained by entering Hidden Palace Zone and having all seven Chaos Emeralds. You are then required to complete a Special Stage.
Sonic glows the colors of the Chaos Emeralds in this state, can perform a "double jump" of sorts that can be aimed, and destroys any Badniks on screen. He also cannot drown.