Painkiller

 is a deathstreak in Call of Duty: Modern Warfare 2. It divides all given damage by three (not including knives, riot shields and falling damage) when they spawn for the third time without getting a kill. It only lasts for ten seconds before the player's maximum health returns to normal. While Painkiller is in effect, the player's screen is tinged yellow with a pill showing how many seconds are left in the deathstreak reward. When shooting a player with this deathstreak, a small pill will appear below the crosshairs. This deathstreak replaces Juggernaut perk from previous Call of Duty games. It is a little less effective since it's temporary, but it gives a much greater health bonus. In most game modes, the player will respawn away from the action, making this deathstreak useless though this perk can be useful if an enemy kill streak is in use such as a helicopter or AC-130, giving the user enough time to react and find cover. It is more helpful in crowded games like Free-for-All where players often spawn close to each other, and small maps are more common.

The extra health may confuse experienced players who know exactly how many shots are needed to kill a non-painkiller enemy, causing them to instinctively stop firing before actually killing the painkillered player giving them a chance to recover and fire back

Tips

 * Painkiller will prevent most one-hit-Kills, even from a silenced sniper rifle round to the head in Hardcore. Even a direct hit with a grenade launcher will not kill someone with painkiller. However, some weapons (most shotguns for example) can still kill in one hit even with the added protection.
 * Painkiller will not prevent the user from dying if hit by an AC-130's 105mm Howitzer or 40mm gun.
 * The Riot Shield (much like the knife) ignores the effects of Painkiller and will still kill an opponent in 2 hits.
 * Using a tactical insertion to spawn near an anticipated concentration of enemies (such as a flag in Domination) will help you enter combat before Painkiller expires.

Trivia

 * Painkiller may be a reference to the somewhat historically questionable origin story of the M1911 .45 caliber pistol. During the Filipino-American War, the under-armed Moro guerillas would often rush American soldiers, targeting the officers, armed only with machetes called Bolos. The officers' .38 Long Colt rounds would often hit but fail to immediately stop or kill the Moros who would continue attacking. It was rumored the Moro were taking drugs or painkillers which allowed them to continue fighting. However, there is little historic evidence that the Moro were actually taking drugs and the apparent "Painkiller" effect was a combination of the psychological effects of the Moro warrior culture, the underpowered .38 round, the nature of .38 revolvers at the time and the difficulty of making solid hits under stress. The larger .45 caliber semi-automatic pistol was rushed into service but was not used before the war ended.
 * Online it is often refered to as "jugger-noob," "pain pills," or "being on the pill."