The Action Gauge, also called the Chaos Gauge in Shadow's case and the Super Gauge in the Super State, is a game mechanic that appears in the Sonic the Hedgehog series. It is a gauge that measures the amount of special power the playable character holds.
The Action Gauge consists of an oblong rhombus with a gauge inside it, which can be filled with a cyan-glowing bar representing the available power. Located in the right proportion of the Action Gauge is a 3-light display called the Level Indicator.
In Sonic the Hedgehog (2006), the Action Gauge's function is to depict the energy available for the player to perform certain actions, such as Sonic's Energy Field, Shadow's Chaos Boost and Silver's Psychokinesis. Using these actions depletes the power depicted in the Action Gauge and once it empties, they can no longer be performed. All three characters can refill the Action Gauge by collecting Chaos Drives, Gauge Ups and Light Cores, though Sonic and Silver's Action Gauge automatically restore themselves very fast over time (In Silver's case, it will only restore if he is on the ground).
The Level Indicator serves an additional function to Shadow. For Shadow, the light display shows which Chaos Boost level he is currently on, which is indicated by how many of the three lights are glowing red. Note that the higher the Chaos Boost level is, the faster will the Action Gauge be depleted.
Although the instruction manual of the game mentions that Custom Actions should also consume the Action Gauge's energy when used, this is not possible and Custom Actions can be used indefinitely in gameplay due to misnamed variables in the game files.. When these variable names are corrected, the Action Gauge still starts full when one enters a stage but will deplete ten percent of the gauge for each usage of any Custom Action. Unlike the Energy Field but like Shadow's Chaos Boost, the Action Gauge can only be replenished by Chaos Drives, Gauge ups and Light cores though it takes a little more to fill it up using any of the three (except Gauge ups). Relocating to another section or losing a life in a stage returns the gauge filled.
The small rectangular bar positioned below the main gauge on the Action Gauge works as a gauge in the Xbox Live Arcade demo of Sonic the Hedgehog (2006), though it does not work perfectly. The Level Indicator also works for Sonic, but is always at the first level, unlike in the final version of the game.