Flare

The Flare is a piece of equipment in Halo 3 and Halo 3: ODST. It is used to blind enemy personnel.

Overview
Flares are visually identical to Radar Jammers and Power Drains save for their varying colors; flares have a yellow glow. When a player picks up a Flare, the equipment piece is represented on the HUD by a circle with multiple rays coming from it.

Though Flares can be Forged into every map in the game, they do not appear in any maps by default. They used to spawn in Guardian and Isolation, but were removed during a title update as a result of the Equipment Jumping glitch, which allowed players to use Flares and other items to reach inordinate heights in Matchmaking. Because of this, Flares are only useful in modified map variants and some Campaign levels.

It functions in a similar manner to a stun grenade, blinding foes and allies alike. Unlike stun grenades, however, Flares do not "pause" the vision of affected players. Instead, Flares only blind players who look at them and players within close proximity -- in other words, the Flare exhibits a temporary but continuous area of effect. (It could be considered to have two areas of effect: players in extremely close proximity are completely blinded, whereas players who are a few feet away can restore their vision by simply looking away.)

It is mainly used to surprise and blind your opponents. However, a planned strategy and a close range weapon or a type of one-shot kill weapon can be used to almost certainly dispatch an enemy in conjunction with a flare. Without a very effective weapon, it is just a nuisance, hindering you just as much as your opponent and is useful for planning your escape from your enemies. Flares serve as effective distractions. Bungie employee Jaime Griesemer described one strategy: "See a bunch of people guarding the flag? Throw the flare down. By the time the Flare's gone, their flag is too."

Disadvantages
When deploying a Flare, a player will almost always find themselves within the Flare's area of effect; this causes the user to be blinded. A blinded player's HUD, Motion Tracker, and reticule, however, are unaffected. This allows a target to simply look around rapidly, shooting when the reticule turns red. Similarly, both the user and the target of a Flare can turn around rapidly before or as it activates, mitigating the resulting loss of vision. These traits serve as both disadvantages and advantages, depending on who uses them. Such strategies work best when used against people who are unfamiliar with them.

Strategy

 * In CTF, the user can throw the Flare in the flag room, run in, and collect the flag (if the user can take the flag and run away in the right direction).
 * When deployed in narrow corridors, its very useful for blinding everyone in it.
 * If used in small areas in Infection, its good for making quick escapes.
 * Useful in conjunction with a short range weapon against a sniper, throwing the Flare at the sniper makes it impossible to see you.
 * A simple but annoying tactic, is in Forge, to set the Flare to respawn instantly after being picked up. The player can then continue to throw Flares in the same place and create a miniature sun. The normal extreme light of the Flare is amplified and the entire screen goes completely white, with the exception of the motion tracker and HUD, of course. It can be used to simply annoy other players, or if used with a partner, a sniping asset. Silhouettes of the players in the Flare's radius are visible, and for a sniper located farther away, its an easy way to rack up kills. However, the Flare-dropper can also be killed by accident by the sniper, thus ending the "flashlight of death".
 * On the level High Ground, a Flare can be used with the Portable Gravity Lift to penetrate the Turret/Sniper Guards.
 * Best used on the level Guardian, since it has many small rooms and hallways.
 * A Flare can be used to draw both allies and enemies to a location.
 * Two players can cooperate, using a Flare and a Radar Jammer to capture a flag with ease.
 * If one is attentive, even when blinded by a Flare you can see the red names of your enemies. Paying attention to your reticule will allow you to find targets as well.
 * If a player accidentally looks at an active flare, looking away will not completely get rid of the effects.

Trivia

 * In Campaign, the Flare has no effect whatsoever on enemies. They will be able to shoot you regardless; this is because AI-controlled NPCs use a raytracing-like algorithm to detect targets, and this algorithm does not take light or color into account. It seems as if the Flare's sole purpose for existing in Campaign is for enemies to use them against you. However, at some point, it will sometimes make Grunts and Brutes dodge or panic, the Grunts flee and the Brutes go berserk.
 * The Flare is visually identical to the Radar Jammer and Power Drain save for its yellow glow. The Flare's color denotes its purpose, as a bright yellow is commonly associated with light or the Sun.
 * Although the Flare blinds targets completely, they can still see their HUD, Motion Trackers, and reticules. For Spartans, this may be because such images are uploaded directly into their brain, bypassing their eyes.
 * The flare was cut from Matchmaking as a result of the Equipment Jumping glitch.
 * In reality, the Flare's effects would not blind a fully armoured Spartan, as the MJOLNIR armour's visor automatically polarizes in extreme light.
 * If an active Flare gets struck by a Plasma Grenade, the grenade will cease to exist and the Flare will continue as if nothing happened.