Ring

One distinctive and recurring feature of Sonic games are the collectible golden Rings (sometimes referred to as Gold Rings or Power Rings) spread throughout the levels. This gameplay device allows players possessing at least one ring to survive upon sustaining damage from an enemy or hazardous object. Instead of dying, the player's rings are sacrificed; in most Sonic games, a hit will cause the player to lose all of their rings, although in certain situations (such as the Special Stages in Sonic the Hedgehog 2) and throughout certain games (such as Sonic Triple Trouble, Shadow the Hedgehog, Sonic and the Secret Rings, Sonic Unleashed, and Sonic Blast) a hit only costs a set number of rings rather than the entire collection. In more recent games, usually only 20 rings are now lost.

Upon colliding with a hazard, the on-screen character is thrown backwards and given a momentary period of invulnerability (represented by a rapid flashing between visible and invisible). The dropped rings burst out of the character in a circular pattern and bounce around the environment, flashing for a few seconds before disappearing entirely. During this brief period, it is possible for the player to recover some of the rings they lost. Generally fewer "recoverable" rings are displayed on-screen than the number actually lost (usually a maximum of around 20; fewer in Sonic games on 8-bit consoles, about 50 in Sonic Rush).

Certain causes of death cannot be prevented by holding a ring, including being crushed, falling into a bottomless pit, failing a mission held through a time limit and drowning.

In line with many platform games, collecting 100 of these common collectibles will usually reward Sonic with an extra life. Certain titles in the series often reward the collection of other quantities of rings, often in conjunction with the Chaos Emeralds; usually, at least fifty Rings are required to access the Special Stages in which the Chaos Emeralds may be obtained, or to utilize a character's super transformation.

The origin of the rings, like the Chaos Emeralds, is never revealed during the game series, although Sonic's Uncle Chuck, Tails, and Tiara Boobowski are shown to create rings. In addition, even Sonic characters are shown to have thought they came from a different world in official media. They are not often referenced by characters during gameplay, but they are used as currency in Chao Black Markets and in shops in Sonic the Hedgehog (2006) and Sonic Chronicles: The Dark Brotherhood. They are also mentioned to be a monetary system in Sonic Heroes. In Shadow the Hedgehog, Dr. Eggman collects them for prizes in his game-filled carnival base, and is distressed when Shadow takes them from him during the "Egg Dealer" boss battle. Rings can also be used to buy Extreme Gear in Sonic Riders and Sonic Riders: Zero Gravity.

Other continuities
Rings are also canonically equipped to characters throughout the media. To spin dash in any cartoon, contrasting to all the games, Sonic must have a power ring and can only collect one at a time. In the SatAM cartoon, Sonic also comments that the rings only last for 24 hours and work only for him. Amy and Shadow also wear rings on a daily basis, Amy probably to protect herself, and Shadow to retain his abilities (they have been with him since his creation).

SatAM, Archie Comics, and Sonic X
Despite being a gameplay feature in the video games, the Power Rings do not make as large an appearance in the animated shows. In "SatAM" and Sonic X, Sonic can absorb a ring to give him extra speed and power for a short while. In SatAM, they are found in a lake, which they are taken from by either Sonic or Tails (this is the only instance in the franchise where Sonic commonly wears a backpack for easy access). They are also used to restore free will those who were Roboticized. Also in this series similar Rings are used by Dr. Robotnik to incapacitate prisoners. In Sonic X, Rings are made from Chaos Emeralds and usually given to Sonic by Tails, apparently produced by a generator installed in the Tornado 2.

In the Archie Sonic the Hedgehog comics, the Power Rings are identical to those found in SatAM. However, the comics take it a step further, naming the Power Rings as a fifth element aside from the traditional ones of fire, water, air, and earth. Because of this, the Power Rings are eagerly sought after by the wizard Ixis Naugus. Massive quantities of Rings, gathered all at once or one at a time, can also produce a super transformation or other effects, such as communication with the Ancient Walkers. These rings have also been shown to offer a kind of protection, as shown when Sonic's parents kept their free will when all the other Robians lost theirs, they also have been shown to offer wisdom and even grant wishes to the holder.

A few children's novels and comic books claim that the rings were created by Sonic's Uncle Chuck to boost Sonic's speed and power.

Sonic the Comic
In Sonic the Comic, Golden Rings are an apparently naturally-occurring phenomenon of Planet Mobius. They were used by Doctor Ovi Kintobor in conjuction with his Retro-Orbital Chaos Compressor (ROCC) to transfer most of the evil energy on Mobius into six Chaos Emeralds. They possessed strange properties (possibly inherently, or possibly as a result of their use in the ROCC) and emitted special Ring Energy. Robotnik was able to use the rings to power his Neutrino Accelerator. According to Tails, this Ring Energy was also responsible for Sonic's first transformation into Super Sonic, although Sonic had absorbed so much Ring Energy over the years that later transformations were caused purely by stress.

During the explosion of the ROCC, Kintobor's personality was once somehow imprinted on a Golden Ring. Porker Lewis was able to use this ring to create the Kintobor Computer. The Kintobor Computer program was temporarily re-downloaded onto a ring when the Freedom Fighters' secret base was discovered by Robotnik and had to be evacuated.

Trivia

 * The familiar sound effect used for rings has been adopted for use in cash registers.
 * Rings can also have other purposes. For example, Shadow's Inhibitor Rings keep his powers in check as long as he wears them.
 * sonic and the black knight is the first games to rplace rings with some thing else like faries