The Giant Ring is an object that appears in the Sonic the Comic series published by Fleetway Editions. They are large variations of the Golden Rings which are capable of transporting a person virtually anywhere.
The Giant Rings resemble normal Golden Rings, except they are much larger. If a person has accumulated enough Ring Energy from Golden Rings when passing through the Giant Ring, the person is instantly transported to a location of their own choosing. The more ring energy that is stocked up, the further can a person be transported.
Sonic once used a Giant Ring as a short cut to instantly travel from the Green Hill Zone to the Marble Zone, but accidentally collected too many rings and got himself sent to the Special Zone. The use of Giant Rings eventually phased out of use as the Freedom Fighters began using the Star Posts for instantaneous travel between Zones.
Following an attack on the Floating Island by the Death Egg II, Knuckles uncovered an ancient Giant Ring covered in ancient Echidna writing. He accidentally activated the ring and got himself transported to the Special Zone.