Painkiller is a deathstreak featured in Call of Duty: Modern Warfare 2. It divides all the damage recieved by the player by three when the user spawns for the third time (second with Hardline Pro) without getting a kill. It only lasts for ten seconds before the player recieves the normal amount of damage.
While Painkiller is in effect, the player's screen is tinged yellow with a pill showing how many seconds are left in the deathstreak. When shooting a player with this deathstreak, the Painkiller icon will appear below the cross-hairs. This deathstreak replaces Juggernaut perk from previous Call of Duty games. Some consider it less effective since it is temporary, but it gives a much greater health bonus, dividing all damage given from a weapon by three. In most game modes, the player will re-spawn away from the action, making this deathstreak almost useless, though it can be useful if an enemy killstreak is in use such as a Chopper Gunner or AC-130, giving the user enough time to react and find cover, or if the user uses Tactical Insertion, as they can spawn closer to the primary fighting.
Painkiller is useful in more popular games like Free-for-All where players often spawn close to each other, and small maps are more common. It is also a very effective way of countering players who constantly rush, as the additional health upon spawning coupled with the rusher's likely use of Lightweight allow the player to survive long enough to kill them. The extra health may also confuse experienced players who know exactly how many shots are needed to kill an enemy, causing them to instinctively stop firing before actually killing the player and sometimes even reloading, giving the Painkiller-using player a chance to escape or to turn around and shoot back.
Painkiller, along with Copycat, was supposed to be a perk in Call of Duty: Modern Warfare 3, but was cut for unknown reasons. Painkiller is still usable, but only in modded custom game modes by putting it as a gun proficiency. It has no emblem, but does have a countdown, and makes the edges of the screen turn yellow.
Painkiller will prevent most one-hit-kills from a silenced sniper rifle round to the head in Hardcore.
The Juggernaut was originally a usable character model in multiplayer that would increase the player's health. However, this proved to be overpowered and was replaced by Painkiller. The character model was reused and put into Special Ops.
The yellow tint that appears when using Painkiller is similar to that of Call of Duty: Modern Warfare 3's Ballistic Vests, which also gives a similar effect to the player.