Red Star Ring

Red Star Rings (レッドスターリング), more commonly referred to as Red Rings and originally Special Rings, are unique Rings found in several games in the Sonic the Hedgehog series. Red Star Rings are often used to unlock special bonuses.

Sonic Colors
The Red Star Rings first appeared in both versions of Sonic Colors where they are named Special Ring. Five Special Rings are found in each level in both versions (except Terminal Velocity). Some of these Special Rings are located in easy locations while some will need the usage of a Color Power and some are in hard-to-reach locations. Special Rings will also give a Special Bonus of 30,000 points. In the DS version, if all are collected in an Area, pictures in the gallery are unlocked. When all of the Red Star Rings are collected in the DS version, Sonic unlocks the Infinite Boost. When all the Red Star Rings are collected in the Wii version, all the stages in Eggman's Sonic Simulator are unlocked. When all of the Sonic Simulator stages are completed, Super Sonic mode is unlocked.

Sonic Generations
The Red Star Rings return in the console/PC version of Sonic Generations where they are called Red Star Rings. There are five Red Star Rings in each act, collecting one unlocks music or concept art. If all the Red Star Rings are collected in an act, one giant Red Star Ring will hover over the stage and a new skill will be unlocked.

If the player talks to one of Sonic's rescued friends when they have the icon of the Red Star Ring above them, they will give him/her a hint as to where they are.

Sonic the Hedgehog 4: Episode II
Red Star Rings make an appearance in Sonic the Hedgehog 4: Episode II. One Red Star Ring appears per act and the only purpose they serve in this game is for 100% completion as well as an achievement/trophy.

Sonic Jump (2012)
In the 2012 remake of Sonic Jump, there are three Red Rings to collect in each act.

Sonic Dash
Red Star Rings appear early along the first run of each day in Sonic Dash, but they can also still be obtained by completing certain objectives and can be used to unlock new characters or to buy re-tries for whenever you fail.

Sonic Lost World
Red Star Rings reappear in Sonic Lost World and are used to unlock content. Each Zone has five Red Star Rings to collect. Some Red Star Rings can be obtained only when Sonic uses the Parkour system and some of them come out of bells Sonic chases along from the stage. Collecting all the Red Star Rings in the Wii U version unlocks the World's Chaos Emerald. However in the 3DS version, collecting all the Red Rings in a World will unlock a Bonus Zone.

Sonic Jump Fever
Red Star Rings appear in Sonic Jump Fever as collectible items placed in the Zones although a limited number of these does so per day. They can also be obtained occasionally from Daily Rewards or from the Daily Spin. However, if the player equips him/herself with the Hero Rare Chao or Hero S-Rare Chao, it can reveal hidden Red Star Rings in the Zone. They are mainly used as the in-game currency to purchase Gold Rings or use the Spin (when the free Daily Spin or video to obtain a free spin are both unavailable). Red Star Rings can also be purchased by the player using real money.

Archie Comics
In the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics, the Red Star Rings are unique Power Rings produced by Lake of Rings. Unlike normal Power Rings, the Red Star Rings have potentially much higher energy outputs. They were first discovered by Dr. Ellidy a few weeks after his Lake of Rings seemingly dried out.

They were introduced in Sonic Universe #72 and played a major role in the Spark of Life Arc.

Trivia

 * According to Blaze in the console/PC version of Sonic Generations, there are objects like Red Star Rings in her world.