Playing Possum

A small-scale exchange of fire has just taken place. The bad guys see one of the heroes lying on the ground, apparently dead, with a sword or whatever sticking out of him or her.

They approach the apparent corpse, or corpse is brought to them via The Body Bag Trick. As they stand over them, the "corpse" opens their eyes. And beats them up.

In the Real Life, this is a war crime and has been since 1977. The Laws and Customs of War state that those soldiers that are hors de combat ("out of the fight") a category that includes prisoners, the severely wounded, the dead and ejecting aircrew—although not paratroopers -- are not to be attacked. Feigning that status is perfidy and highly illegal, since it would lead to the other side killing the genuinely wounded on the spot (which is a war crime too) to make sure. Of course, fictionally (and non-fictionally), you're often up against people who aren't signatories to the Geneva Conventions...

Although, playing dead in Real Life does have its quirks in specific situations. Such as when being confronted by certain animals, like bears, who are hardwired to mostly take interest in prey that look alive and kicking. If you can pull it off long enough, the animal in question will most likely leave your body alone, giving you a chance to escape. Similarly, it is legal in war to pretend to be a corpse until the enemy soldiers leave or stop paying attention if you use the opportunity to retreat instead of ambush.

Note that Playing Possum is a phrase inspired by the Virginia opossum, which famously feigns death and produces a rotting smell. Proper possums are not noted for employing this strategy. Unfortunately for the opossum, this response to danger is involuntary and often leaves it incapacitated in a dangerous situation.

See also I Surrender, Suckers. Compare Defensive Feint Trap. Contrast Finger-Twitching Revival.

Anime and Manga

 * Jotaro Kujo from Jojo's Bizarre Adventure plays dead in order to draw his opponent, Dio Brando, within attacking range. As Jotaro currently has a bunch of knives in his body, he can't afford to take any more hits from Dio, so he waits until Dio is practically inches from him and then uses Star Platinum to deliver a skull-shattering punch.
 * attempts this during the finale of Magical Girl Lyrical Nanoha StrikerS so she can perform one last sneak attack on, though since she was struck by stun rounds, it's more accurate to say that she was playing unconscious instead of playing dead.
 * Hei from Darker than Black does this in the second episode, at which point we and some hapless goons learn both that his Badass Longcoat is bulletproof and that he doesn't really go in for that whole "fighting fair" thing.
 * Samurai Champloo :

Film

 * In Rambo III, Rambo shoots down a huge Russian gunship with a small bazooka, by playing dead until it approaches within point-blank range.
 * Robert Carlyle's character in period film Plunkett and Mcclean does this at the end of the film.
 * The bad guys sometimes pull this trick as well. See Hot Shots! Part Deux for a spoof of this.
 * In The Patriot, Col. Tavington does this at least once.
 * Karl does this in Die Hard. Like the previous example, it goes rather poorly for him.
 * In Fatal Attraction, Glen Close appears to be dead—but wakes up and attacks Michael Douglas again.
 * In the movie Runaway Jury,  plays possum to stab a hitman's leg.
 * Liam Neeson's character Bryan Mills in the movie Taken does this in one scene. After Mills massacres all the bad guys in the kitchen, the men standing guard outside run in to find the cause of the commotion. They see a room filled with dead bodies. Suddenly Mills begins firing from underneath a corpse.
 * Played straight in Enemy at the Gates, with two characters both pretending to be dead in order to eliminate a German officer. On the other hand, the German soldiers were bayoneting corpses just in case.
 * uses this trick against near the end of Kill Bill Volume 2.
 * In Plunkett and Macleane  uses this to lethal effect during the finale.
 * In The Dark Knight  uses this to gain control of a gang.
 * Zombieland and it's golden rule, the doubletap, is key to avoiding this kind of situation with zombies.
 * In Shooter, Bob Lee Swagger is badly wounded after being shot twice, but as a highly trained Marine Scout Sniper he is far from disabled. He plays up his injuries so FBI Agent Memphis will get close to him, then quickly disarms him and steals his car.
 * The Big Red One. German infantry lay doggo around a knocked-out panzer and its dead crew, planning to ambush the main troops once The Squad of Americans have finished their recon. Fortunately Lee Marvin's character notices the mixed uniforms (panzer troops have red piping on their shoulder tabs, but infantry have white).
 * The Thing does this. Most notably with Norris-Thing. It doesn't quite work out as planned, though. Instead of being treated like a dead body, Norris-Thing is shocked with a defibrillator and retaliates by biting off Doc's Arms when he goes in for a second shock.
 * It was more successful with the attack on Bennigs by what was assumed to be a completely dead and burned body.

Literature

 * This is used in the book The Lord of the Rings: The Two Towers, during the siege of Helm's Deep. After Aragorn and Eomer have run off a group of Uruk-hai, a dozen of them pretend to be dead and leap up on them when their backs are turned - only to have Gimli pop up and cleave off two of their heads in a typically Dwarven display of awesome.
 * In the novel Robert Heinlein Time Enough For Love, Lazarus Long, having lived for 2,000 years and fought in numerous wars, mentions that he knows to "waste" a bullet in any "corpses" he runs across during battle.
 * In the WW 2 novels by Sven Hassel, it's a sign of a combat veteran that he never passes an enemy corpse without putting a bullet into it.
 * Tsubodai comes up with such a plan in Wolf of the Plains when the Mongols move to attack the Shizuan fort. Those with the hammers feign death and, when the Xi Xia soldiers come to loot their corpses, they jump up and attack the no-open fort with the rest of the Mongol army waiting just around the mountain.
 * In Dan Abnett's Warhammer 40,000 Gaunt's Ghosts novel Blood Pact, when Maggs attacks Kolding, he goes down. Gaunt tries to stop Maggs, and Kolding reappears to clock Maggs from behind; he explains to Gaunt that he thought it wiser to stay down—and that Maggs had clearly been hallucinating.
 * in Harry Potter.

Live Action TV

 * In Star Trek episode "Journey to Babel", Kirk defeats an untouchably-fast enemy ship by shutting down the Enterprise ship's power and pretending to be dead, causing the enemy ship to close in for the kill; this allows the Enterprise to disable the ship with one well-placed phaser shot.
 * In "Balance of Terror", the Romulan commander orders debris ejected into space (along with the body of his friend the Centurion) to make it look like his ship has been destroyed so that the Enterprise will drop its pursuit. The trick doesn't work.
 * Robin Hood:
 * In Babylon 5, Sheridan destroyed the Minbari warship Black Star by sending a distress call from his crippled ship, and then destroying the Minbari warship with mines as it homed in on his signal. Word of God is that the Minbari ship's response to the distress call was in order to find and destroy the surviving ship, not to rescue the crew.
 * Justified as well in the series, as the Minbari had demonstrated it over and over. Also, Sheridan's distress signal was genuine. He simply knew that the Minbari ship would likely find them before any rescuers did.
 * A random, unnamed soldier does this in an episode of Torchwood, Faking the Dead in order to attempt to kill an alien. Most of the guards stationed at the entrance to a stockpile of United Kingdom nuclear weapons have all been slaughtered by the attacking alien, who has now crossed the entrance and is approaching the facility itself, when suddenly one of the soldiers lying on the ground bounds up, grabs his assault rifle, and starts gunning right into the aliens back. It fails (Damn forcefields), but still, Badass.
 * In the Doctor Who serial The Invasion of Time, one of the savage Gallifreyans, after telling Leela I Will Only Slow You Down.
 * One of the pirates in Meglos.

Professional Wrestling

 * This is a trademark trope of Bret Hart. He would often fake being injured far more severely than really was (usually with the leg) in order to sucker his opponents into pinning predicament. During his feud with Vince McMahon in 2010, he executes a Batman Gambit revolving around this trope to screw his Arch Enemy.

Tabletop Games

 * Dungeons & Dragons even has "Feign Death" spell.
 * Also, some liches developed "Feign Destruction" spell - they can simply use a mindless animated skeleton as Body Double in the first place, but even with magic buffs it may go down too easily. "Dream of the Earth" spell from Dragon acts as Feign Death for someone else, and also gives the target delusion of being killed.

Video Games

 * Can be done in Unreal and Unreal Tournament. In the earlier editions of the game, it caused the player to rather obviously fall over very slowly without bending any joints, leading to a "hinges in the feet" type of effect. Later games corrected this with the use of a ragdoll engine, though it returns in Unreal Tournament III.
 * Hunters' Feign Death move in World of Warcraft. Like similar moves in other MMOs, it causes monsters to stop attacking the Hunter, thinking him dead, although it can fail.
 * In the early days it was pretty effective in PvP as well. Well timed Feign Death could make the opposing player think their enemy is already dead... until the realized the Hunters' pet was still attacking (normally auto dismissed at player death), and that Hunter that was on the floor is now using Aimed Shot (charging, really powerful attack back in the day) on you... ouch! Trying it these days will now get you the following statement from your opponent: KEK! N00b!
 * Truth in Television, as it turns out, World of Warcraft saved the life of one kid. report here
 * Similarly, you can do this in Tenchu: The Wrath Of Heaven/Return From Darkness (same game, different consoles).
 * This was one of the powers of the Spy in the original Team Fortress, and returns in Team Fortress 2 with the Dead Ringer.
 * Used in the Call of Duty series; some enemy soldiers, when wounded, will lay on the ground dying, but pull out a grenade or pistol and wait for the player to get close. It's also possible to do this in multiplayer, where if critically wounded your character can either pull out a pistol and try to take the enemy down with them (Last Stand), or drop a live grenade and blow themselves up (Martyrdom).
 * In World At War, the Japanese sometimes do this without being wounded first; at one point in the first mission, the player and his squad happen upon what appears to be a group of corpses. Within seconds, a flare shoots up, blinding everyone while the soldiers get up and surprise attack the unprepared Marines.
 * Done in Tomb Raider Anniversary with the final boss. She goes down and Lara slowly approaches with her guns drawn. The boss turns her head and then quickly leaps to Lara, grabbing her by the neck, and tossing her aside while taunting with "I cannot die, you fool. Sooner or later, you'll run out of bullets!"
 * This may be a lampshading of the fact that Lara never runs out of bullets (at least for her basic guns).
 * Dead Space has necromorphs do it, but it falls flat in part because after the first time people are never ever trusting a dead body.
 * On the harder difficulty, however, the necromorphs will do it after you've shot them. Remember kids: In this game, just because you shoot its head off and it falls down doesn't mean it's dead.
 * Splicers start doing this regularly by the end of BioShock (series), but it's certainly a scare the first time. "We tricked you, monster!"
 * This may trick your eyes, but not your interface: your targeting reticle will turn red when it aims at a seemingly dead corpse that is really a live splicer in ambush. Regular corpses have it keep its standard white color.
 * Near the end of Prototype, Alex pulls this off to get close to Gentek director McMullen.
 * The Rogue's Feign Death talent.
 * The zombies in several of the Resident Evil games have a tendency to do this, falling to the ground after you've damaged them enough, but getting back up a short while later (or gnawing on your legs if you get too close). The key is that they're not really dead until you see the spreading pool of blood beneath them.
 * Jim Chapman of Resident Evil Outbreak can do it right back to them, plummeting to the ground to make zombies ignore him for a while. It's balanced by the virus gauge climbing at a much faster rate, so you can't just lay there forever.
 * Bad Girl will drop at random and start crying, though there are times her hands are completely off her bat, which means she's open to a Travis Touchdown spanking. If she's got one hand on her bat, approaching her is a bad idea.
 * In the Monster Hunter series there's the monster Gypceros, who will feign death once he recieves enough damage. If you fall for it and start carving him, he will flail around wildly, dealing huge damage if you're too close. You can tell if he's just pretending by checking your quest info or by throwing a paintball at it: if the dot in the map is pink, he's still alive, if it's grey he is really dead.
 * In Dragon Age, the rogues have an ability called "feign death," which is Exactly What It Says on the Tin.

Web Comics

 * In Kaspall, successfully resorts to this as a way of gaining information from people talking near his body.
 * In No Rest For The Wicked, November's technique when facing a bear. Her sister had recommended it in the past.

Real Life

 * Truth in Television just recently: at least one "dead" Islamic terrorist turned out Not Quite Dead and killed at least one U.S. soldier. Despite the perfidy and the laws of war mentioned above, the squad was savagely smeared by the media when the same soldiers, days later, shot a "corpse" for making a sudden move. Fortunately, it ended up into nothing.
 * Another example of Truth in Television - during World War Two, Japanese soldiers often played dead and ambushed US troops when they passed, or took advantage of corpsman willing to treat them by letting off grenades - a cruel move. One Marine veteran wrote of possum squads - Marines who, after a battle, were tasked with bayonet "dead" enemy corpses.
 * In 1984, "Subway Vigilante" Bernard Goetz reportedly told one of his vanquished muggers "you don't look so bad, you could use another" before firing another bullet at him. As the mugger was only shot once, it is unclear if Goetz hit with the first then missed the second, or missed the first and hit the second, and if the mugger was down at the time or he was still legitimately defending himself against a threatening target.
 * When the State of Qi during China's Spring and Autumn period was entangled in a Succession Crisis in 685BC, the two pretenders, with their retainers, were racing back to the capital to be enthroned. When a retainer of Pretender Jiu saw Pretender Xiaobai, he promptly shot Xiaobai—but only hit his belt buckle. Xiaobai quickly played possum to fool Jiu's faction and won the crisis.
 * A college football defensive coordinator was suspended for a game after it surfaced that he ordered his players to feign injuries to slow down another team's hurry-up offense, designed to keep the defense winded and unable to substitute players. However, feigning injuries in and of themselves carries no penalty, unless they're blatant. The only "penalty" for going down with an injury is to leave the field for at least one play...an outcome the player faking the injury likely wanted to do in the first place.
 * Germans started doing this in World War Two. It wasn't long before American soldiers, when in doubt, bayonetted enemy corpses.