Noob Combo

EMP Combo is a term coined shortly after the release of Halo 2. However, the original idea came from Halo: Combat Evolved, albeit a modified version. It is typically used to refer to the combination of a Plasma Pistol overcharge and a semiauto or burst-fire weapon, such as a Magnum or a Battle Rifle, though it can also refer to other weapon pairings, but not as commonly.

Background
An example of the EMP and Melee combo J3-DrCwBomA The basic technique is to sneak up on a player and hit them with a Plasma Pistol overcharge. The overcharged plasma bolt will drain the victim's shields, allowing the attacker to finish them off with a headshot or melee. The most common EMP combo is the combination of a Plasma Pistol and Battle Rifle. Another popular combination is of the Plasma Pistol and Magnum -- dual-wielded, of course, to remove the need to switch weapons -- as the Magnum is sufficiently accurate at medium range.

Halo 3 's Plasma Pistol was altered; the overcharge shot's homing ability was weakened, and the projectile's speed was reduced. A new feature was also implemented: "holding" an overcharged shot will continuously drain a Plasma Pistol's battery. This effectively caused a drastic decrease in the use of the emp combo.

In Halo 3: ODST and Halo: Reach, the lack of dual wield makes this technique slightly harder than before. However, in the Campaign, enemies are usually stunned when their shields are drained, giving the player time to switch to a finishing weapon.

Evasion
In Halo 2, a player can block an EMP combo through various means. One method involves a defender who dual-wields weapons and melees when the attacker's overcharged Plasma Pistol shot is about to hit. The melee forces the defender to drop a weapon; if timed right, the attacker's plasma bolt will hit the defender's dropped weapon as it falls. Plasma Rifles work well, due to their bulky heads.

Alternatively, a well-timed grenade can block an overcharged Plasma Pistol shot. Plasma and Frag Grenades both work, though it is not known which is more effective. Some argue that an overcharged plasma bolt homes in on Plasma Grenades better, while others contend that Frag Grenades are thrown faster. In Halo 3, this counter-strategy (when used with a Frag Grenade) has the added bonus of injuring the opponent -- if the defender's grenade is thrown just as the plasma bolt is fired, the bolt will detonate the grenade in front of the attacker.

When the aim is to stop a combo in progress (after having been hit by the overcharged plasma shot), a defender can lob a Frag Grenade at the attacker and then crouch. The attacker's attempt to line up a headshot will be slowed down by the defender's crouching, and the grenade will hopefully distract the attacker long enough for the defender's shields to recharge somewhat. Plasma Grenades should not be used, as they take longer to detonate.

Uses
Despite the negative stigma from sore losers surrounding the EMP Combo, it remains a very common tactic in multiplayer. It is also extremely useful when playing the games' Campaigns on higher difficulties, especially against powerful enemies such as Zealots and Spec Ops Elites. It is of limited use against either varieties of Brute Chieftains, but against the rest of the Brute ranks found in Halo 3 and Halo 3: ODST it is devastating, removing their armor making the follow up headshot, usually lethal. Halo 3: ODST encourages the latter usage, granting players an achievement for earning ten kills with the combo. In Halo:Reach, the noob combo is useless against regular Brutes, as they do not have shields, and their head is armored. Brute Chieftains and Captains have shields, though their heads are still covered by a helmet, again making the technique rather useless.