Active camouflage

The Active Camouflage power-up is a light-bending energy stored in a small, glass-like pyramid in Halo: Combat Evolved and Halo 2, although in Halo 3 it is suspended in a spherical force-field. It is similar to the way a Covenant overshield functions. When the player breaks the active camouflage container (done by simply walking over it), the energy envelops the wearer and bends light around the skin, armor, or shielding, conforming to its user's form and rendering them almost invisible. This effect wears off as the energy dissipates.

Function
The Camouflage covers the entire body. The coverage does not extend to the entirety of the user's equipment. Human weapons won't give away the user's location as much as Covenant weapons do. Weapons with illuminations like the Plasma Pistol and Plasma Rifle can be seen, as can the Energy Sword, giving away the user's position. Also, if close enough, the character's outline is seen faintly and looks like a moving silhouette. Yet it's hard to see the outline and the "ghost" from a far angle. Even on a scoped weapon, like the Sniper Rifle or Battle Rifle, it can be difficult to see a camouflaged opponent. When any projectiles pass through the shielding (whether by firing a weapon or being shot), it is temporarily deactivated, making the user visible.

The technology can be utilized on Human armor systems, such as the MJOLNIR armor, but the UNSC has only developed a rough equivalent, the Camouflage Cloak.

Some Elites have active camouflage generators, as do some SpecOps Grunts. . The Arbiter has old armor with an obsolete active camouflage generator that needs to recharge after using the camouflage for too long. In Halo 2, it is noted that the Arbiter's armor, while possessing an in-built active camouflage generator, is not permanent until turned off, unlike the more modern generators used by SpecOps Elites. There is a circle on the player's HUD that shows the amount of time left for both the usage of the active camouflage and the recharging sequence. The Master Chief can gain this ability with the Envy Skull.

When playing as the Arbiter, using any attack will cause the active camouflage to deactivate, and the player must wait for it to recharge before using it again.

Use in Campaign
If the active camouflage is active during campaign, your are completely invisible to the AI enemies unless you fire your weapon which will deactivate the camouflage for a short amount of time. Active camouflage is only usable in campaign when you are playing as the Arbiter in Halo 2, pick up Cloaking in Halo 3, and in four levels in Halo: Combat Evolved: Truth and Reconciliation, Silent Cartographer, 343 Guilty Spark, and Assault on the Control Room. In Halo 3, Active Camoflage is a piece of equipment that can be picked up much like the Bubble Shield or other items. What makes this beneficial is the item can be used when needed, not just when available. The user can hold on to it until it is required in a situation when he's drastically outnumbered. Activating the Cloaking can even the odds or avoid contact all together.

Active Camouflage and Shielding
An odd discrepancy is present in the difference between Halo: Combat Evolved and Halo 2 active camouflage. In Halo, Stealth Elites using active camouflage had no shielding whatsoever; furthermore, Elites were the only Covenant to possess it. However, in the last level, an Elite Flood Combat Form was seen with an Active Camouflage, but this was presumably an infected Stealth Elite. In Halo 2 active camouflage was seen in use by both Elites and Grunts, during The Arbiter and part of Regret.

In "A Day At the Beach," an Elite Minor is seen engaging his own active camouflage at the expense of his shields (though when the camouflage seems to be shorted out by the plasma grenade explosion his shields are reactivated).

It can be conjectured from this evidence that perhaps all Elite armor has active camouflage systems installed, but in all but the highest echelons of Elite rankings the power drain deactivates the shield in favor of the camouflage. Only Ultra Elites and Special Operations Elites seem to have enough power in their armor to run both systems at the same time.

In Halo 3
The Active Camo is no longer contained inside a pyramid. Instead it appears as a large, glowing sphere with what appears to be containment devices around it in Halo 3 multiplayer. Unlike past Halo games, active camo is not found in campaign. In campaign, Active Camouflage is replaced by the Cloaking equipment, which functions in the same way as active camouflage once used. Melee attacks, shooting, throwing grenades, and using equipment will negate the effect of the power-up.

The quality of camouflage in custom games may be set to three different settings :
 * Poor Camo: The player has camouflage that might fool a Grunt.
 * Good Camo: The player has camouflage that will fool an attentive Elite.
 * Invisible: The player is perfectly invisible when not shooting.

Trivia

 * By changing the graphic's card settings on Halo PC, active camouflage users appear as a big, single-color figure and are very visible.
 * Active camouflage covers the Energy Sword in Halo 3, unlike in the previous games where it remains fully visible.
 * Active camouflage is similar to the invisibility of the Predator in the Predator series of movies.
 * On 343 Guilty Spark if you go right off of the fallen tree towards a small indention in the hill, you will find an Active Camouflage next to a pipeline.
 * Active camouflage generates heat, which can be taken advantage of by the use of infrared equipment by UNSC forces.
 * The Separatist Phantom in Halo 3 has its own Active Camouflage generators onboard for various stealth missions.