Type-1 Antipersonnel grenade

"Get it off! Get...it...off!"

- A Grunt after being stuck with a Plasma Grenade

"Demon Flare!"

- Elite referring to the plasma grenade

The Covenant Type-1 Antipersonnel Grenade, also known as the Plasma Grenade, Sticky Grenade, Holy flare, Holy light, or the Demon flare by the Covenant is similar to the UNSC Fragmentation Grenade in that it is a hand-thrown Anti-Infantry and Anti-Vehicle weapon.

Overview
The Plasma Grenade (or sticky as it's sometimes referred to) is a specially designed grenade that adheres to its targets. Once it hits a target, the plasma grenade will immediately bond to it, making any removal impossible. The bonding mechanism holds its attraction, except to seemingly static objects, such as walls, until detonation, making it impossible to avoid its deadly explosion. Therefore, if you have been "stuck", it is a good idea to take out as many opponents around you to reclaim points. Although it will bond to any target it hits, if it attaches to a piece of armor or a weapon, removing said articles will allow one to distance themselves from the explosion. Once the plasma grenade has adhered to the target it kills instantly, so all there is to do is kiss your butt goodbye if your the one stuck.

The "sticking" mechanism is complex enough to allow the plasma grenade the ability to distinguish between targets and inanimate objects. For example, it will stick to a soldier or a vehicle, but not a tree or a wall etc. This does not, however, allow the grenade to act selectively. The plasma grenade will not distinguish between friend or foe so accuracy and caution is strongly advised when throwing it, so as not to betray your allies.

The plasma grenade possesses a timer. It has a three-second fuse that counts down at the point of activation. A manual activation via a small button or a stimulated activation, such as another explosion or gunfire, will set the detonator and start the countdown. Delayed activation can also set the detonator after it either sticks to a target or otherwise comes to a rest. It is possible to tell if the grenade has been activated. A densely small and bright cloud of plasma emission will leak around the grenade as the explosive reaction takes place inside. This cloud will gradually grow to a larger diameter after each second of the countdown. A low sound is emitted by the grenade when activated, followed by two rapid beeps and a high-pitched whine just seconds before the explosion. This is the plasma grenade's standard process of detonation.

The Plasma Grenade appears to have two settings: the standard three-second fuse and a delayed manual detonation. The latter is seen in Halo 3 by suicidal Grunts hoping to ensure their enemy's death by exploding right next to them also known as kamikaze. In addition, the plasma grenade can be destroyed by being shot (Easily seen with the Sentinel Beam).

Also, some characters in campaign cannot be stuck. Brute Chieftains have immunity from this until their armor is knocked off. However if the Brutes shield is broken (i.e in Halo 2, Tartarus can be stuck if his shield is broken), you can still stick them.

Advantages
Sticking an enemy with the plasma grenade, will always result in instant death (except for hunters).Also, except when (in Oddball, or Juggernaut) the player is stuck and the option "Ballcarrier has extra life" is chosen (in Halo: CE), but in this situation the ball carrier will only have 1 bar of health. Even a fully shielded Spartan or Elite (except on higher difficulty levels) cannot withstand a stuck plasma grenade. In Halo 3, high ranking Brutes on the harder difficulties can withstand a player's grenade with Mythic (death skull). Also, higher ranking Grunts on Easy, can withstand grenades thrown by their Grunt brethren if it sticks to them with Mythic. In Halo: CE Grunts will sometimes run for surrounding elites when stuck, pleading him to remove it. This results in both the grunt, the elite and the elite's team, if any, being killed.

Disadvantages
The plasma grenade's bright blue glow and longer delay fuse allows enemies to easily notice and avoid it. It cannot be used around corners, as its bounce is negligible, and it does not roll. A player wearing a fully charged Overshield may be capable of surviving the blast even when stuck. Also, if a smart enemy is stuck when they are too close they can simply run toward you to catch you in the blast zone. In Halo 2 and Halo 3, a primed plasma grenade in flight can be detonated mid-air by another explosion. Weapons capable of this include the Rocket Launcher, Brute Shot, Missile Pod, Frag Grenades, other Plasma Grenades. The Plasma Grenade will not stick to certain types of armor such as that of a Scarab or a Brute Chieftain's. When thrown at them, the grenade will fall to their feet, and they will probably notice it and move out of the blast radius. Ballistic or explosive weapons such as a shotgun or Brute shot will remove the plating allowing the grenade to stick. If someone throws a plasma and it hits the wall, it can bounce off the wall back down and adhere to the thrower. Also, if the opponent notices you, he/she will probably take immediate evasive action. As you will probably miss if they dodge, they will be relatively unaffected due to the tiny blast radius.

In addition, due to the long explosion time, if you intend to flip a vehicle by planting a grenade, the driver will have plenty of time to swerve and dodge. This also applies for infantry, as Grunts will dive out of the way if not stuck.

Also sometimes when trying to stick an enemy you might commit an error if you throw it to an enemy's weapon, the plasma grenade will bounce of the enemies weapon and will cause the grenade to have little effect or the enemies will dodge it.

Another thing is if in Halo 2 you stick a higher ranking Elite such as an Ultra it will not kill him and really takes two grenades for an ultra and higher ranks, this is a disadvantage because this makes it harder for a player to kill an Elite of higher rank.

Sticking a Brute may prove difficult, Brutes have be known to move and dodge a lot in Campaign so you have to time it right when throwing a plasma grenade to a Brute.

Effects on Health
It has been shown that, prolonged exposure to the radiation emitted by plasma grenades, without proper protection, can cause a deviation in the neural electric pathways of the user, a disorder called Boren's Syndrome. This disease can be fatal if the person does not get treatment. Sergeant Avery Johnson is the only known living person to have Boren's Syndrome. However, this explanation may be a cover up to protect Johnson's status as a Spartan I.

Theory about "Stickiness"
''Note: The following is speculation.

The plasma grenade, may stick by producing a thin layer of plasma which, when in contact with a target, fuses to the target. The reason the plasma grenade, sticks to vehicles and characters may be due to an ability to sense Body heat and the heat from vehicles engines is most likely what causes it to stick. Since a "dead" wall doesn't emit heat, it will; however, stick to the "living" walls of a Flood Hive. One problem with this theory is that it will stick even to exposed skin (on Grunts, Jackals, or Marines as an example) even though there is no metal to fuse to - it would be nearly impossible to fuse the grenade to flesh using heat alone.

It is also theorized that there is a complex internal mechanism built into the grenade that gives it this characteristic. A gravity generator may be built into the core of the device, giving it its own force of attraction. This artificial force of attraction is highly concentrated, which is exactly why the grenade is impossible to remove.

Another interesting thing, to note the fact that when a plasma grenade is primed, it does not stick to the thrower. A theory for this could be that the grenade must be primed touching something emitting heat, then leaving the heat-emitting object, thus activating its "stickiness," and finally landing and sticking to another heat-emitting object i.e. the target. This is even better proved by the fact that it will stick the person who threw it if it bounces back at them i.e a wall.

It's possible, that the grenade has an adhesive activated by a timer. Once the grenade is activated, this timer is initiated, giving a few seconds for the thrower to release the grenade. Once the timer has run out, the adhesive activates and the surface of the grenade is as made sticky as glue by the activation of the adhesive. Although, this theory doesn't explain the environment/character principles of the grenade.

Another theory is that the Plasma Grenade has a energy shield hybrid shell to bounce off of walls and an internal magnet to pull it to vehicles and armor.

Another theory states that the Plasma Grenade detects low-level and medium level electrical pulses that are in living things and that are in shield and vehicle technology. Jackal Gauntlet Defense systems emit a high rate of energy, enough to repel Human Projectiles, while the MJOLINR Armor, Elite Combat Harness, and Brute Combat Harness all are damaged by projectiles. This could mean that the Plasma grenade cannot stick to a high level electrical pulses, such as the ones that are in Jackal Gauntlets, but have sufficient energy to stick to low to medium power energy shields as well as vehicles. This would also explain why Brute Chieftains cannot be stuck, as their armor have extremely powerful energy shielding, albeit the fact that it can still be damaged by human projectiles.

Trivia

 * It is possible to stick a weapon then trade the said stuck weapon and live. The grenade will stay on the other weapon. Although switching for your secondary weapon won't help.
 * In Multiplayer if you stick 5 people in a free-for-all (i.e. Lone Wolves) match you receive the Lee R. Wilson Memorial Achievement.
 * In Multiplayer, if you stick an enemy with the plasma grenade you are awarded with the Grenade Stick Medal.
 * In Multiplayer there is sometimes an error where the stuck grenade will only kill the opponent, and not explode. There are also occasions where a Plasma Grenade will pass through the opponent or if it does stick, it may not kill them for an unknown reason.
 * Occasionally, in Halo 3, Plasma Grenades will actually bounce off players for an unexplained reason, presumably lag. Shortly after the bounce, the Plasma Grenade may teleport back onto the target.
 * Another error, (usually found in the campaign) is where the grenade may entirely disappear if not looked at.
 * In Halo: Combat Evolved, the Plasma Grenade's explosion was more of a blue cloud and was also very powerful, similar to that of a Needler in the same game. The size of the blast animation and radius also got smaller going into Halo 2, and smaller still in Halo 3.
 * There is a glitch in Halo 2 where grenades very occasionally pass through the player.
 * In Halo: CE, plasma grenade damage, like a Needler detonation and plasma pistol overcharge, is classified as an EMP (electromagnetic pulse) and instantly drops all shields, even a full Overshield. The same held for grenades that were dropped. This was removed in Halo 2 and 3 (except for the plasma pistol overcharge), making it less effective against infantry.
 * In Halo: CE multiplayer, the human frag grenade is considered more effective against large groups of infantry, while the plasma grenade is used for single opponents or fast-moving vehicles.
 * In Halo: CE, a plasma grenade inflicts 4 times the damage to a shielded Elite. So if an Elite is damaged by a plasma grenade at all when its shields are up, it will die, with few exceptions. However, the damage multiplier is normal when damaging flesh, so on higher difficulties an Elite has a better chance of surviving a plasma grenade explosion when its shield is down.
 * In Halo 2, when the Covenant use plasma grenades in battle, they will shout phrases as they throw them, such as "cleansing flame", "flare" and "holy light". This is similar to their belief of Halo. They will still shout demon flare even if it is thrown by an ally, albeit rarely.
 * If John-117 throws a plasma grenade, the Covenant will call it a "demon flare".
 * When an NPC is stuck, they will frequently have some type of reaction to being stuck.
 * Occasionally, if two plasma grenades are thrown in succession at the same spot; one will detonate, launching the other far into the air. The airborne grenade will explode in mid-air, causing a "fireworks" effect. This is easiest to perform in Halo: Combat Evolved.
 * If you stick a charging Hunter with a plasma grenade the Hunter will instantly turn around, exposing its back, when the grenade explodes. It is unknown why this occurs.
 * It is possible to stick a Hunter on the back of the head. It will charge at you, but if you manage to get away, then the Hunter will die immediately.
 * In Halo:CE if you throw a frag grenade where a group of plasma grenades are, the detonation of the frag will make the plasma grenades explode. The same occurs in Halo 3, but only during the Campaign.
 * In Halo:CE, Plasma Grenades take 4 seconds to detonate. In Halo 2, they take 3 seconds. In Halo 3, they take about 2 and 1/2 seconds.
 * In Halo 3, when you throw a plasma grenade, it makes a long beep before exploding.
 * Plasma Grenades are favorite weapons of the "Ghosts" of multiplayer maps, nearly always sticking people in the face and chest.
 * In Halo 3, physics made it possible that if timed correctly at a position, when an opponent's Plasma Grenade is aimed at a player's left elbow (virtually), and when the grenade itself is about a foot away and the player throws his/her own Plasma Grenade, then both plasma grenades will stick each other and explode midway in the air.
 * It is possible to stick the grenade while it is in the opponent's hand, meaning they get to throw two grenades at you.
 * It has been found to be possible to stick yourself. Often achieved by bouncing a grenade off a wall, or by getting (un)lucky and throwing one onto your knee. All grenades, even Plasma grenades also become deflected of a bubble shield so this is also an unlucky way to stick yourself.
 * The above trick can be accomplished at all times if the player crouches and aims as far down as the HUD allows then throws the grenade which attaches to their foot.
 * Like all grenades,it can be shot and detonated by a weapon. A Battle Rifle works best.
 * It can be used for the Warthog Jump.
 * Occasionally, in Halo PC the Plasma Grenade will stick but will not explode and instead just disappear, called a "dud". It is unknown whether this is intentional or due to lag or a glitch.
 * Chieftains can only be stuck on their weapon, feet, and head (once the headdress is knocked off), although extremely difficult to do so.
 * Kamikaze Grunts will activate two plasma grenades at once and charge the player, they are the only species known to wield two grenades at once (this occurs only in Halo 3).
 * Avery J. Johnson supposedly contracted Boren's Syndrome from detonating every Plasma Grenade in a crate stolen from the Covenant at Paris IV.
 * Plasma Grenades only stick to "organic" objects (Sangheili, Jiralhanae, Humans, etc.) and bounce off anything else, with the exception of vehicles.
 * On one side of the Plasma Grenade, a Forerunner Symbol like that of a Halo:CE Elite is visible.
 * When stuck, Grunts in Halo:CE may shout, "Ohhh, not again!". This may indicate the Covenant's belief in reincarnation. That, or it may simply be a humorous anecdote inserted by a Bungie employee.
 * In Halo 2 if you throw a grenade (when you don't have any) while looking down your torso will raise from your hips and you legs will extend. This is due to the model stance change. Others will see your weapon lowered.
 * There is a glitch involving getting the sticky off you when you get stuck. To achieve this, get stuck first (should be easy enough, just stand still when they throw a sticky at you). Then, rush towards the nearest teleporter and get through it. Your sticky should have "magically" disappeared. This only works for Halo PC. Also, you must be close enough to the teleporter so that you can get through before the explosion.
 * Through the previous glitch, you can also effectively "fall through" Blood Gulch. Time the explosion so that when the sticky blows, you are in the teleporter. You should fall, waving your arms, toward a bottomless end. This glitch is, of course, much easier with the Banshee Fall Glitch. However, this method does not involve vehicles.
 * In Halo 3 the plasma grenade can be shot out of the air.
 * In Halo 3, sticking a Plasma Grenade to the Ghost's front "shield" is not fatal. This is most likely because the shield protects the driver. However, a stick anywhere else on the ghost will kill the driver.
 * In Forge on Halo 3, there is a trick people can use with stickies to act as a kamikaze. Move right up against a wall make sure you're facing the wall), and throw a sticky at the wall so that it bounces off and sticks you. When that happens, go into editor mode and fly around. Whenever you feel like it, change back into player mode and the sticky will explode (it's funny to get right up in a player's face when this happens).
 * In multiplayer, the plasma grenade is often referred to as a "blue spider".
 * They are also referred to as "blueberries" or "stickies".
 * It is possible to get a sticky stuck in a grav-lift. it will float in the grav-lifts gravity stream until an outside force pushes it out. This is inadvisable to do with 2 grenades to 1 grav-lift, as they will eventually stick to each other. This trick can be used in machinimas as an ambiance tool.
 * Exclusively to Halo 3, The plasma grenade makes a beeping sound before it blows.
 * In Halo:CE, if you stay on the Pelican on 343 Guilty Spark, when the pelican crashes, throw a grenade at the end of the map(the grey part), and the grenade will brighten, but it won't explode.
 * There is much debate about which grenade is easier to score a stick with between the Spike Grenade (type-2 Antipersonnel Grenade) and the Plasma Grenade (type-1 Antipersonnel Grenade).
 * Many players prefer sticking targets with the Plasma Grenade rather than the Spike Grenade.
 * According to the Halo 3 game manual, the Plasma Grenade has the second highest kill and casualty radius (4m and 12m respectively) of all the grenades in the game.
 * In Halo 3 meta-game, if you take out a shielded enemy's shields with a plasma grenade explosion (without sticking them), and then headshot that enemy, you will receive the EMP Medal. This must be done against a shielded enemy (i.e., a Brute).