Z-4190 bubble shield

The Bubble Shield is an anti-artillery and personal defense device developed by the UNSC's Office of Naval Intelligence branch.

Overview
The Bubble Shield projects a transparent, slightly white/gold tinted protective sphere around the user. The shield itself is similar to a geodesic dome, made of tessellating hexagons. The shield protects against bullets, explosions, lasers, plasma, flames, grenades, and other projectiles used primarily by the Marine forces of the UNSC and the Covenant. A bubble shield is used in the original teaser trailer for Halo 3. It is shown being used by the Master Chief to stop an incoming Plasma Mortar. However, in the video the bubble shield looked like some type of grenade (that's just the way it looks before activation), leading to rumors that it would be one of the new grenade types. Vehicles and players however, are still able to pass through it. After a significant amount of time has passed it will collapse. Covenant Loyalists, mainly the Brutes, have been known to secure human weapons and equipment for their own ends, the Bubble Shield being one of the most common.

Development
The Bubble Shield was created by ONI. However it is not known if it was created using human technology or if it was reverse engineered similar to how the MJOLNIR Mark V energy shields were created. The Bubble Shield technology is nearly identical to the Covenant Shield Doors in function.

Deployment
Despite being UNSC technology, UNSC Marines are never seen deploying it during the Campaign, while Brutes deploy it often. At least one or two Brutes in a Covenant pack always have a Bubble Shield on hand. Brutes generally activate their bubble shields immediately, following aerial insertion and when in large numbers.

Unlike the Heroic DLC "shield doors" vehicles are able to pass through the Bubble Shield. Once, inside, if the vehicle, or anything else then damages the shield generator itself on the enclosure of the bubble, the shield will then collapse on fired detonation.

Multiplayer Strategies
The Bubble Shield is an incredibly useful piece of equipment in any Multiplayer game or match. These are a few yet vital tactics that you should know if you want to use the Bubble Shield to its full potential. If you have been in a close range fight with another player and your shields are down, it is often a good idea to use a bubble shield to give your shields time to recharge before you go frag your next victim. Also if you have a Shotgun or Energy Sword or a Gravity Hammer as your secondary weapon and a player with a regular weapon (Assault Rifle or Battle Rifle) is running to you, drop the shield so that they will be forced to come through the shield to finish you. Right before the player gets to the shield, pull out your sword/shotgun and blast them when they step through. If you do not have a close range weapon, use this same strategy except with a Frag or Spike Grenade. Time the grenade so that it will explode right as they step through while you step out the other side of the shield to avoid damage. Another good strategy is to throw a spike grenade into the bubble; The blast/spikes will be contained in the shield. The spikes will also fly and hit any player within the bubble causing massive amounts of damage even if it doesn't kill them outright but be ready with a weapon to finish off those that do survive the blast to quickly rack up the kills. This trick has been nicknamed by many Halo players the Shrapnel tactic.

Another method that is very useful is the man cannon-bubble shield combo. In Valhalla and Narrows, there are campers who will hide near the spot where the man cannon shoots people. If a player uses a bubble shield first and throws it onto the cannon, the player can safely land without being immediately killed by grenades or players.

Also, you can start a fight inside, and before you die, toss a grenade (any type, preferably plasma grenades); and your weakened foe will die with you. A good way to kill someone in a bubble shield is with the Sniper Rifle. Make sure you are in a safe position so you don't get assassinated and aim at the player's head. This is quite easy because people usually don't move when they are in a shield. Keep on the player's head and as soon as the shield disappears shoot them. While it may seem very simple, most players do not see this coming, and never expect it. Another fun way of getting through an opponent's bubble shield is to get a vehicle and drive into the player hiding in the shield. This works particularly well with a Warthog or Ghost and is very fun to watch as the victims believe that they are perfectly safe. Another strategy is to rush into the shield and step back right when you're in front of it, if it works the other player gets out of the shield, giving you an open shot. Also, it is possible to poke the barrel of a sniper rifle out of the shield while staying safely inside it yourself.

One strategy is, activating a Bubble Shield in a doorway so if you and your team were under fire they could use this shield to get away from the enemy. When an enemy is coming at you while you are in a bubble shield, throwing a grenade and moving out of the bubble shield depletes the enemy's shields so you can kill them with a single melee hit or head shot. On close-quarters combat maps like Guardian the Bubble Shield can be used to distract enemies while you sneak up behind them and kill them from the posterior flank. Also, in close-quarters maps the Bubble Shield can cover an entire room for protection. Another strategy is to block heavy weapons such as Rocket Launchers and Spartan Lasers with the Bubble Shield causing you to survive and them to waste a shot that would've been otherwise useful.

Campaign Strategies
When fighting large numbers of Brutes, the bubble shield is useful as it protects you from all sides. However, certain berserk Brutes can go inside the sphere and beat you down. It is particularly useful against Drones, partly because they usually surround you, and partly because they will almost never attempt to go inside the sphere. Do be aware, however, that after 19 seconds, the Shield will deactivate, leaving you wide open to an attack. Another situation in which the bubble shield is useful is protecting you from a Scarab detonation. It will stop the explosion from harming you completely, unless the explosion starts on the inside of the bubble shield. So it is advised that you at least exit the Scarab before using the bubble shield. Beware that the Scarab's debris will fall through the Bubble Shield, however, and could kill you. Another strategy is to use a Bubble Shield as a stepping stone, breaking up combat and allowing the player to use the Bubble Shield to fall back on. This is especially useful at the end of The Storm, where there are large, linear sections.

Cons of the Bubble Shield

 * Enemies can walk freely in and kill you.
 * The shield does not stop enemy vehicles from entering.
 * You cannot return fire from inside the bubble's proximity.
 * The Bubble Shield only lasts a short 19 seconds.
 * If either you or an enemy throws a grenade inside the Bubble Shield, it stays inside and will most likely kill almost everyone in the shield at the present time. Also, the grenade may detonate the Bubble Shield, increasing the damage, making it all the more dangerous to stay inside of it.
 * Flood Forms will usually and typically just run inside the Bubble Shield and attack you unlike other enemies who usually wait for it to disappear.
 * The generator is very delicate so if you shoot it, it will blow up.
 * If surrounded you are particularly vulnerable.
 * An easy way to kill a Bubble Shield along with those in it is to use an explosive. Grenades and Rockets work well, but if you have the fear of dying, quickly enter the shield, throw a spike grenade inside (it'll most likely stick to you if thrown on the shield's wall) and watch the kills rack up. The reason for this is the grenade's spikes, they bounce off the walls and off the floors, killing most inside the shield.
 * Most players will start a "staring contest," where they refuse to come in, and you usually (or the person in the shield) refuse to come out. Try your hardest to avoid this. In Team Games (especially ranked), they can call for backup, someone could sneak in or jump from a height, making it difficult to guard the shield.
 * If an opponent has a Grav Lift, they can throw it near the shield generator and force it to fly up, leaving anyone previously inside the shield defenseless. Anyone unaware of what had just happened is fairly easy to defeat, especially if it was thrown to gain a chance to recharge their shields.

Trivia

 * In an early Halo 3 build the Bubble Shield was able to roll like the Power Drain, and the actual device had the same appearance, but had orange lights instead of blue. It was also originally in grenade form before being changed.
 * This shield resembles the description of the Onyx Sentinel shields in the Eric Nylund novel Ghosts of Onyx.
 * With no damage modifiers, a melee with most weapons will destroy the shield generator.
 * It is sometimes believed to be a Brute invention since Brutes always activate these devices, however it was developed by ONI.
 * The original bubble shield was smaller and was in the shape of a 'V', as seen in the Starry Night video. Also it would stab into the ground, rather then just lay on top of the ground.
 * In the Beta Version of Halo 3, the Bubble Shield did not glow gold and was able to protect you against the turrets guarding the outer perimeter of the multiplayer map Snowbound. This, however, changed when the game was released for gameplay reasons.
 * You cannot actually disable a Bubble Shield by throwing a Power Drain at the generator, but you can leave the opponents inside vulnerable with drained health
 * The Bubble Shield is movable by the use of gravity lifts.
 * The Bubble Shield logo, along with the Trip Mine logo, is a Halo 3 multiplayer emblem.
 * A possible glitch is that if for example, a Brute Chieftain with a Fuel Rod Cannon is shooting at you and you deploy the Bubble Shield before it hits you, you will not die. In this situation, even though the shield appears to be in the process of expanding, the effects of the shield have already been activated.
 * The Bubble Shield can cover an entire Warthog from an attack.
 * The Bubble Shield will make a static sound when shot by a rapid-fire or automatic weapon (i.e, Assault Rifle, Battle Rifle).
 * There is a glitch that if a Bubble Shield is placed on the lower deck of an Elephant on Sandtrap, the Spartan laser can then penetrate the shield.
 * A common strategy is to use Shotgun in conjunction with the Bubble Shield. Enemies would have to enter to fight you, and you kill them with the Shotgun immediately.
 * When inside the Bubble Shield, a distinctive hum can be heard, most likely coming from the generator.
 * When a Power Drain is thrown at the Bubble Shield's generator, the Bubble Shield will move over a few inches.
 * The Bubble shield in the Halo 3 Starry nights TV ad is also smaller than the finished Bubble shield (as can be seen in the picture below where John 117 is just covered by it and it seems more like a personal device).
 * If you look closely at the Bubble Shield, you can see that there are actually two layers of shielding that make it up.
 * Range of the Bubble Shield is close to three meters.
 * In the machinima Red vs Blue, the Bubble Shield was agent South's armor ability.

Images
 Image:Bubble Shield in Action.jpg|The Bubble Shield. Image:Bubble Shield.png|The Bubble Shield HUD icon. Image:Avatars_Halo_Halo3_Shield.jpg|The Bubble Shield activating in the Halo 3 trailer. Image:Bubble Shield Demonstration.jpg|The Bubble shield can block a Particle Beam Rifle shot. Image:1179249572.jpg|The Bubble shield is capable of blocking practically all forms of attack throughout it's duration, including Spartan Lasers. Image:Brute activates a bubble shield.jpg|A Brute activates a Bubble Shield. 