Active Camouflage is a tool used in the Xbox game Halo and its successor Halo 2. In Campaign mode it is an ability inherent in Covenant Elite units; in multiplayer it can be picked up by walking over the appropriate object, which appears as as a transparent pyramid with a blue globe suspended inside. Active Camouflage makes the player invisible, but refracts light from behind slightly a la Predator, thus hiding the player from foes. Also, Active Camouflage is deactivated if you start fighting.
