Painkiller

Painkiller is a deathstreak featured in Call of Duty: Modern Warfare 2. It divides all given damage 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's maximum health returns to normal.

Overview
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 respawn 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.

It 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.

Tips

 * Using a Tactical Insertion to spawn near an anticipated concentration of enemies (such as a flag in Domination) will help one enter combat before Painkiller expires.
 * In smaller maps (for example, Rust and Scrapyard), Painkiller can be very effective if used as the player is very likely to run into an enemy within the ten second time limit.
 * Painkiller is very effective when getting out of a spawn trap (very common in Domination games). Also, if the enemy team has someone into the player's spawn location (the one person normally won't change the spawn positioning), Painkiller can be an effective way of stopping the player in the spawn point.
 * It is very effective in taking down snipers considering a sniper rifle will take numerous shots to kill the individual. Not only will this give the player time to take cover, but considering that the sniper will probably miss more shots as the player gets closer, the player should have time to line up a shot to effectively take out the sniper.
 * Online, this deathstreak is looked down on by many experienced players due to the strength of it, the ease of achieving it, and how soon it is unlocked. It grants what many consider an "unfair" advantage over players, albeit temporary. This is countered by sitting a certain distance away from likely spawns, preventing the user achieving the full effect of the deathstreak. But the previously stated tactic prevents the player from playing the game for periods of time in order to counteract painkiller.
 * Even though players should realize that they are far from invincible when using this deathstreak, it might make sense to rush into danger and try to get as much possible use out of Painkiller before it expires.
 * This deathstreak reward can be coupled with the Last Stand Tier 3 perk to really confuse and frustrate enemies.

Trivia

 * Sticking a player with Semtex does not do enough damage to kill a player using Painkiller.
 * Painkiller will not prevent the user from dying if hit by an AC-130's 105mm Howitzer or 40mm gun.
 * The SPAS-12, M1014, and Ranger shotguns can all kill a Painkiller player instantly without the Stopping Power perk if at a very close/point blank range, as the SPAS and M1014 do a max of 320 damage per shell, and the Ranger does max 450, 900 with Akimbo.
 * Painkiller can be used to survive in the radiation areas on Wasteland and Afghan.
 * The Riot Shield ignores the effects of Painkiller and will still kill an opponent in two hits, or one hit in Hardcore. The Knife also ignores the effects of Painkiller.
 * Painkiller will prevent most one-hit-kills 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 active.
 * 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.