"If your attack is going too well, you have walked into an ambush."
— Murphy's Rules of Combat
Two enemies are fighting, though only one is doing so furiously. The other is going for pure defense, not so much fighting as retreating as fast as prudence will allow. With such a resounding rout, the attacker presses his advantage and just before landing the finishing blow... notices he's followed the defender into a nest of the defender's allies. Oh Crap.
Basically, an opponent lures their enemy into a trap by either feigning retreat or weakness. Once the attacker has moved into position, or spent most of their energy/ammo attacking, the defender turns the tables by going all out, using Geo Effects, or calling his allies in ambush.
This can be done either by heroes or villains, though heroes tend to consider such tactics "dishonorable". When done to a hero, the trap's fatality depends on the hero's level of Plot Armor, but will usually give them at least a good run for their money.
Expect at least one ally to say "This is too easy", and later yell "No, stop! It's A Trap!" and get either ignored by the hero or heard too late. This can also take the form of an enemy enticing their attacker into "winning" Pyrrhic Victory before they realize what just happened.
One of The Oldest Tricks In The Book.
This is similar to Playing Possum and I Surrender, Suckers, but uses a retreat or "completely defensive stance" as bait rather than playing dead or feigning surrender. However, this tactic is perfectly legal under the laws of war, while feigning surrender is not.
Compare Punch! Punch! Punch! Uh Oh... and Lured Into A Trap. One of the variations of the Distress Call is a fake call employed as a lure. See Attack Reflector for effects intended to make attackers hit themselves.
Truth in Television of course; this is the essence of strategy #28 of The Thirty-Six Stratagems.
In Rurouni Kenshin, Kenshin advises this strategy if you find yourself in a pitched fight against multiple opponents: run away and then turn around to deal with each pursuer as they attempt to catch up to you (or otherwise find some way to create a one-on-one battle).
Specifically, the difference in speed between each enemy will result in them becoming slightly strung out if they all run at full speed to pursue. If you're a master of one-hit kills like Kenshin, you can quickly put on the brakes, kill the guy in front, and dash off again before the rest can surround you (the worst case scenario when you're outnumbered).
Yahiko puts his own spin on this; he can't use the "take down one guy at a time as you run" strategy, but he can lure his pursuers into a narrow alleyway where they can't all rush him at once.
Shikamaru in Naruto has used some form of this nearly everyone of his fights.
Sakura also used one of these to get rid of Sasori's Kazekage puppet. After getting nicked by one of his Poisoned Weapons she secretly takes one of the antidotes, which Sasori didn't know she had, while hiding behind said (large) weapon and destroyed the Kazekage puppet when it went in for the Coup de Grâce.
A variation on this happens in Tengen Toppa Gurren Lagann, where the Anti-Spiral forces fall easily to Team Dai-Gurren... up until the Anti-Spiral decides to pull the rug. At that point the cannon fodder Anti-Spiral machines become Demonic Spiders, outgunning and outmaneuvering the now-stunned Team Dai-Gurren; only a handful survive the counterattack but they survive to rip the Anti-Spiral a new one, in suitably over-the-top fashion.
The Earth Alliance pull one of these in Gundam SEED, leaving minimal forces at the Alaska base while most of the ZAFT forces stage an attack on it. They wait until ZAFT has nearly taken the entire base, then set off the Cyclops system hidden underground, blowing the base and 80% of ZAFT's fighting force to kingdom come.
In a subversion of this, the Atlantic Federation faction of the Earth Alliance had actually sacrificed their allies by manipulating them into this plot; by deliberately leaving behind forces belonging to the Eurasian Federation at Alaska, they not only convince ZAFT that they're not walking into a Defensive Feint Trap, but also ensure that the bulk of the Eurasian Federation's military forces are blown to kingdom come with the ZAFT forces, effectively ensuring the Eurasians no longer have the capability to challenge Atlantic Federation dominance in the Earth Alliance.
In Code Geass R2, Zero uses this strategy against the Eunuchs, with a twist: said help comes in the form of a citizen population enraged by the Engineered Public Confession the former had set up, with the latter openly admitting to the Empress Tianzi being disposable.
He also tries it against Schneizel, but Schneizel doesn't take the bait.
Yusuke Urameshi ran away once from a super fast foe. He cornered himself into an alley; then, when his foe came to mock him, he shot a burst of his Rei Gun. In the narrow alley, his enemy wasn't able to avoid the shots and was promptly defeated.
A very common tactic in Legend of Galactic Heroes, especially by the FPA. Yang Wenli is especially famous for this. There is actually a battle in the series where an enemy commander — upon seeing Yang's fleet fall back and fearing a trap — is tempted to order a retreat right away.
The Patriot has the American Revolutionary army using its reputation of being composed of untrained farmers and such to its advantage. In one battle, they do a volley, and then retreat, luring the contemptuous British forces into a pursuit... which gets the army, which has fled behind a hill only to set up again, a few free volleys.
Although it probably was a coincidence, done to Han Solo in Star Wars, when chasing a Stormtrooper down a hallway and running into a whole legion of them... hilariously prompting a hasty retreat of his own.
The attack on the second Death Star in Return of the Jedi also counts. The Rebels attacked because they believed the Emperor's Defensive Feint Trap — that the station was incomplete and vulnerable. Instead, not only was the station fully operational, but the arriving Rebels were ambushed by the Imperial fleet behind Endor.
It's also done to a stormtrooper by the rebels on Endor; Han walks up to the guard, taps him on the shoulder, and runs around the corner. The guard follows, into a pack of rebels.
After that C-3PO lures a squad of stormtroopers who went in to capture them, then the Ewoks ambushed them from behind.
In The Avengers, Loki pulls this off by letting himself be captured, thereby leading his forces to the good guys' base because of the homing beacon in his staff.
Under Siege. After Ryback kills several of his men, Stranix gives the order "Do not pursue hostile parties into unsecured areas.". Later in the movie as Ryback is retreating Strannix orders "Do not pursue that man!". His men disobey him and are blown up by a grenade Booby Trap Ryback left behind.
In Waterloo as in real life, Wellington faked a retreat behind a hill. Behind the hill, his army simply changed formation and waited for the ill-fated French charge.
In Sin City John Hartigan acts as if he is too weak to stand, falling to his knees so that the Big Bad will hover over him, giving him an opportunity to get stabbed.
Jerry Pournelle's King David's Spaceship. The barbarians of the planet Makassar lure the Temple guard knights into pursuing them by retreating, then turn and slaughter them.
This happens quite a bit in Romance of the Three Kingdoms; Zhuge Liang was such a master of such traps that the one time his rival came across him sitting on top of a small fort-city playing calming music, gates wide open, and the streets empty except for a few janitors, the rival decided to back off in case of an ambush. (Turned out to be a Refuge in Audacity — Zhuge Liang didn't have the forces for a confrontation, so an attack really would have worked.)
In the Dragonlance novels during the siege of the High Clerist's Tower during the War of the Lance the Draconians pulled this off on the overconfident Solamnic forces.
It doesn't help that the commander of the Solamnic Knights, was just a little bit crazy over having been beaten out for the position of Grand Master of the Knighthood. He decided to launch an attack away from the Tower's defenses in a case of Suicidal Overconfidence, hoping that a stunning rout would sway popular opinion back in his favor. And the garrison, bound to Honor Before Reason as they were, were duty-bound to follow, leaving only the tiny force of Knights of the Crown, who were under the command of Sturm Brightblade, who ordered them to remain behind, to defend the Tower.
Laurana, the Golden General, who takes command of the Solamnic forces after the High Clerist's Tower, returns the favor at the Battle of Margaard Ford. When faced with a massive enemy army that greatly outnumbers her own, she has her silver dragons create an ice dam to block the Vingaard River. Her ground forces then appear to flee in the face of the overwhelming Dragonarmy force. This causes the enemy army to heedlessly enter the now dry river bed in pursuit of her seemingly routed troops. Laurana then has her gold dragons melt the ice dam, creating a massive tidal wave that annihilates the entire Dragonarmy force without her forces taking any losses.
Jochi does this to a group of Russian knights at the start of Bones of the Hills. This is subverted towards the end of the book when Kachiun tries this against Jelaudin. However, since Jelaudin is Genghis Khan's Worthy Opponent, he understands Mongol tactics and realises what they are trying. He thus quickly orders his men to stop their pursuit, forcing the Mongols (see Real Life, below) to deal with the shame of having actually retreated.
The Mongols use the same tactic to better effect in one of the Mars Attacks! novels, where they're using the alien invasion and destabilization of civilization to get their own back.
Warcraft's War Of The Ancients trilogy has the invading demon army use this tactic. Several times. And the overzealous army commander falls for it. Every time.
Resident Crazy Awesome general Mat does this in the the 5th book of The Wheel of Time series. He has his pikemen encounter a large enemy force, attempt to run away, then set up an apparently hopeless defense when they are overtaken. As the enemy approaches without caution, expecting a Curb-Stomp Battle, that's when all the archers and cavalry pop out of hiding.
In A Song of Ice and Fire, Tywin Lannister tries to set up an unwilling Defensive Feint Trap by filling one of his flanks with irregular troops, planning on the likelihood that they'll break and his stronger flank of knights can pin the enemy against a river. He even sticks his unwanted son Tyrion in there, probably hoping that he'll die in the fighting. Ultimately Tyrion works this out and does his best to make sure the flank holds, so Tywin wins the battle anyway.
Happens more than once in the X-Wing Series, most notably at the start of Wraith Squadron. Talon Squadron follows a single wounded enemy fighter into a trap which kills everyone but Myn Donos.
Later used by Wedge himself in the New Jedi OrderEnemy Lines duology. When the Vong stage a ground assault on his Borleias base, he instructs all his defenders to retreat at the same rate, reinforcing weakened areas while ordering the abandoning of more well defended positions. Then, once the Vong have been lured into open ground, the orbiting Star Destroyers open fire...
A small-scale version in Dead Beat of The Dresden Files. Warden Captain Luccio is fighting the Corpsetaker sword-to-sword, and winning handily—in fact, she drives her back into an alley, runs the Corpsetaker through and leaves her for dead. Harry figures out shortly afterward that Corpsetaker threw the fight and let Luccio run her through, then switched bodies with her.
Gordon R. Dickson's The Tactics of Mistake (part of the Childe Cycle) The title comes from the hero's tactical doctrine, which calls for a series of feints, that gradually draw the enemy into an untenable position, at which point he attacks, and demolishes them.
NATO forces use this against a Soviet advance in Red Storm Rising. It works, but the Soviets have enough firepower to plow through anyway.
The MacKenzies use this in the Emberverse against a charge of PPA knights, who are lured into the attack by the illusion that there are fewer archers than in truth there are. The incompetent temporary leader has them take 75% losses in the charge, then has the nerve to claim victory because the MacKenzies left afterward. His commanding officer doesn't take it well.
He used a variation during the Earth/Minbari war. His ship was in fact crippled, and the distress call was very real. He just seeded the area with nuclear mines before sending it, so the effect wound up being the same.
The first shadow-ship he killed, he lured near a jump gate, then touched off his jump engines inside the existing hyperspace window, making this Weaponized Exhaust as well.
Star Trek: Deep Space Nine - "Favor the Bold": The Defiant emits a fake distress call and feigns being disabled to lure Dominion vessels so that a cloaked Klingon vessel can destroy them.
In Community episode Modern Warfare the Chess Club ambushes people by having one member step into a room then immediately run out, where three more wait outside the door. Right before they fall into the trap, Jeff realizes that "He's a pawn..."
In Power Rangers Wild Force, Jindrax and his brother Juggelo, having endured a decisive attack from the Blue and Yellow Rangers, seemingly run away. Blue and Yellow follow, only to be led to the place where their young friend Kite is being held prisoner by a squad of Putrids.
In Mortal Kombat Conquest, Shao Khan lets Raiden beat the shit out him in order to trick him into entering Outworld and losing his advantage.
This is a standard military tactic, called "Feigned Retreat". The Mongols excelled at it. The Islamic armies during the Crusades excelled in it. The Native American tribes were pretty good at it, and they got better when they got horses. Basically, anytime two units were facing off, and one could move faster then the other, this tactic was something to be wary of. The reasons heroes rarely use it are that heroes generally don't like to retreat, even if it would be useful; and heroes generally hate practicing deception.
Over a thousand years ago, Hungarian light cavalry (probably the Huns too) used a variation of this: once the enemy starts to pursue and break formation, the riders turn around on their horses and do the Spam Attack treatment with arrows while still retreating. Such tactics only work if the cavalry is highly disciplined, otherwise the feint could quickly turn into a rout. This tactic worked for a while until the Battle of Lechfeld where the Hungarians suffered a brutal defeat by German knight cavalry, despite having a two-to-one numerical superiority. The trick was that the Germans concentrated on melee combat, not letting their enemies retreat; when the Hungarians attempted it anyway, the knights called the feint and didn't break lines to pursue.
In real life, "heroes" are fine with this. Infantry today learn drills to break contact when at a disadvantage and get back into the fight under better conditions. Historical armies which mastered this tactic were devastating. Viewers hate retreat. In Hollywood Tactics, retreat is synonymous with defeat.
A Real Life subversion: Operation Fortitude was a dis-information campaign that the allies used in WWII to get Germany to believe that they were greater in numbers (Germany believed there were 90 ally divisions in England, when they were only 44) and were poised to attack other locations. The result: Hitler believed that Normandy was just a Defensive Feint Trap to draw fire away from Pas de Calais, where more divisions were waiting. Of course, what Hitler didn't know was that the troops there were just balloon tanks and Hollywood sets. It helped that Gen. Patton was supposedly in charge of the US forces heading for Calais — really an offensive feint trap.
Also, in the last few months, Hitler led his inner circle to believe that all German operations were a massive defensive feint trap. He said they would lure the enemy in, then obliterate them with his new "wonder weapons" and vast reserves. Of course, this was all a delusion. The little markers for those divisions and weapons were still on his map. He was delusional in believing that they actually existed.
A favorite tactic of Erwin Rommel. During the African campaign, when faced with incoming armored assault, Rommel would order his Panzers to retreat, drawing the British into range of his 88mm gun emplacements.
It's pretty much the only winning tactic when you have crappy tanks but excellent Anti-tank guns.
The Carthaginians, particularly those under the command of Hannibal, practiced this. The most notable example would be the Battle of Cannae, in which the Romans pushed back Hannibal's center only to be surrounded by the enemy wings and absolutely crushed. (Cannae is still basic material in officer schools today.)
The reason for that is because it is a tactic that anyone can easily fall for. Ironically, if the Romans simply tried to cut through rather than fight defensively, they could have broken out. Chances are, it would have still failed, but the Carthaginians would not have won nearly as decisively. Either that, or the Romans could have captured or killed Hannibal, turning it into a Pyrrhic Victory
Notably as well, Hannibal had a numerically inferior force so despite having far less men than the Romans, he was able to surround and destroy them.
Which was because most of the Romans at any given time were useless: if you don't have any form of projectile weapon, being trapped in the middle of a position means you can't contribute anything to the fight except waiting for the people between you and the enemy to die so you can get your turn.
In general, heavy cavalry would be taught never to chase light cavalry if it broke away. Heavy cavalry was essentially invulnerable against light cavalry, if the numbers were anything like close, unless it broke that one rule — because speed was the only major advantage light cavalry had. The moment heavy cavalry gave chase, it would be flanked, and cut to ribbons.
In practice, not so much. Especially in Europe, where knights on heavy cavalry had a tendency to chomp at the bit and charge on their own, regardless of good sense and tactics.
Knights tended to consider tactics in general to be cheating, since their entire culture was based on individual valor.
That's more fiction than reality. Most knights were smart enough to break off the charge if they could see it and had enough room. One of the reasons the light cavalry tactic was so effective was due to the difficulty brought about of stopping roughly two-thousand pounds of flesh and steel in time. It still took well trained light cavalry to pull it off, as they had to time it right or risk either losing the chance, or getting rolled over.
Almost happened to the Spanish Armada. If it hadn't been for a sharp-eyed pilot on their flagship, the English would have lured the Armada onto the Owers Bank, a dangerous reef in the English Channel.
An accidental one of these is what basically won the Battle of Hastings for William the Conqueror. Harold's forces had a strong position at the top of a hill, and William's plan to remove them had basically failed because Harold's shield wall was so strong and well disciplined. The battle devolved into vicious hand-to-hand fighting at the shield wall until a unit of Williams, nearly destroyed, turned and ran down the hill. Nearby units (realizing that their flank was now open to attack) turned and ran too. Some of Harold's forces gave chase and in the following melee, the battle completely changed face. Harold's forces who gave chase were essentially butchered, leaving a hole in his lines. William regrouped and attacked again, only this time the now weakened shield wall faltered and he won the battle.
This tactic, while it sounds splendid, was hard to pull off in Real Life because your own men don't know it is a trap, they only know that there are a lot of men with sharp metal objects pointed at their backs. An army has to be well disciplined, and perhaps practiced in this tactic before hand.
Played Straight, and then Happened Accidentally by the Americans at the Battle of Cowpens. The Americans were in 3 lines. The first two lines were to fire and retreat to the 3rd line, in order to tempt the British to charge in headlong for the kill. This trap didn't quite work, and resulted in stalemate. When the British hit the third line, it buckled and fell back, prompting the British to charge for real. The American line halted, about faced, and fired at point-blank range into the British. The battle ended quickly after that.
At Cowpens, one reason for this tactic was simply because the American commander expected militia to run and therefore asked them to just get off a round or two. Behind the militia was a river and a line of Continental Army troops to keep the militia from running too far. The Continentals were well trained enough to recover from a temporary reverse in the manner described.
The Israelis in the Golan Heights pulled off a series of these during the Yom Kippur War.
Wellington's famous "reverse slope" tactic was a variation of this.
The Finns in the Winter War.
A well-done retreat will very likely include a number of these as a routine-even if someone is really retreating, he wants to slow the pursuit down and discourage it.
Happened BY ACCIDENT in a battle during the Revolutionary War in which one of Benedict Arnold's commanders misunderstood an order to march double time away from the British. The Redcoats pursued, thinking they were being routed, when Arnold went to his commander and asked why they were fleeing the field. The commander replied 'does this look like we're fleeing?' and when Arnold realized he had a great opportunity, he ordered the men to stop, turn, and charge the Redcoats. It turned into a complete victory.
Borderline example from World War I: at Caporetto the Italian army was routed and demoralized, but when the pursuing Austro-Hungarians managed to make contact again they discovered that the new Italian commander in chief had managed to regroup his troops and motivate them with fear of what the invaders could do to their families, transforming an actual rout in a trap.
The battle mentioned from the Patriot legitimately happened in the American Revolution.
A well known variation is to use nature as a Defensive Feint Trap. If the defender has no points that it absolutely needs to defend, or it can trust that such points are strong enough to last through an entire campaigning season; and if the area hasn't enough forage to sustain the invader it is commonly used. The invader has to maintain a long supply line draining off garrisons for outposts and escorts for convoys (which are often subject to partisan attacks when this kind of strategy is used). The effect is similar to that of a Risk player who advances until he has no army left. Examples of such strategy include the Byzantine Empire on several occasions, the Americans during the American Revolution, the Spaniards in the Napoleonic Wars and most famously Russia in the Napoleonic Wars and World War II.
This is the strategy behind Muhammad Ali's famed "rope-a-dope" tactic. Used to perfection in the Rumble in the Jungle against George Foreman in 1974, Ali essentially backed up against the ropes and absorbed crushing body blows from the much more powerful Foreman for several rounds. Once Foreman had tired himself out, Ali unleashed on Foreman, who was too exhausted to defend himself, knocking him out in the eighth round.
In Warhammer 40000, this tactic was used against the Tau Commander Farsight by Orks of all people, during the War of Dakka. Such tactics are generally anathema to the Orks, and it's mentioned that the plan would never have worked (or even been attempted) if the Warboss hadn't had a large number of Blood Axes (known for being "sneaky gitz") in his forces.
The Terrans did this to the Vilani fleet at the climax of the Intersteller Wars in Traveller.
In Magic: The Gathering this is practically the entire reason for the "instant" card type which, unlike other types, can be played at any time. Other card types with the ability "flash" can be played at any time as well. In addition, creatures, artifacts, and enchantments often have "activated abilities", played like instants, which one might discount. All of this can be played twice during combat, or can be played in response to something else, the responses following the LIFO rule. And as of Zendikar, there's a new subtype of instants called traps, which are a lot cheaper if your opponent did something during that turn. Yeah, Magic has a lot of room for these.
The prevalence of such cards and strategies which can turn an apparent lead or advantage around in an instant usually cause experienced players to pretty much expect that the other player may pull this, to the point where any lead or impending victory usually means little until the game is actually won.
This is the key weakness of frenzied troops in Warhammer - the general procedure goes: berserkers attack weak troops -> weak troops run away -> berserkers follow into the middle of a large number of heavily armed troops -> meat grinder.
The entire strategy behind the concept of "Pulling" in video games.
To elaborate: "Pulling" is a strategy where you have someone get the enemy's attention and have them follow the puller to a different area. This is done either to fight one enemy, or a small group, at a time from a large group of enemies, or (more rarely) to lure the enemy off of terrain favoring them, and/or onto terrain favoring you. There is, of course, a very famous video of a gaming group building an elaborate plan of attack involving this, as well as defense-in-depth, fire and movement tactics, and about a million other details-before it's all ruined by a party member that's just stupid as hell.
In multiplayer games where the enemies are human, and therefore too smart to simply chase anyone who walks up, attacks once, and then runs away, a genuine attempt must be made to appear weak or show that an ostensible plan has failed; This more difficult distinction is called "Baiting".
MOB As such as League of Legends or DOTA can have this as a key point of strategy. In a game where positioning is crucial, drawing an enemy even just a few virtual meters from safety with the promise of an easy kill on a healer can turn the tide of a teamfight, or even an entire match.
If you hack a turret or camera in BioShock, this tactic can save you quite a bit of ammo. Or, in the case of camera, kill your enemies without ever lifting a finger (or being anywhere near the camera on the map) and plenty of non-hostile drones to catch and hack.
A typical tactic in hack and slash games such as Diablo is to make the enemy forces stretch themselves thin by retreating. It can also be used to lure mooks away from a boss (handy if he can resurrect them), in a cheap but entirely legal exploitation of AI limits.
Also, to change the terrain in your favor. A doorway was one of the more important locations you could have, allowed you to bash at the enemies one by one while being fairly safe and still able to withdraw if it goes bad, as opposed to be being in a corner.
In Diablo II, named monsters have a group of mook buddies that stick to them on an AI "leash." Getting mobbed is a very real danger in this game (each hit disables you for a set amount of time, leading to a Cycle of Hurting if there's a lot of things hitting you at once.) Thus, the pack of normally-laughable fiends who avert this trope tend to be more dangerous than the miniboss itself.
Pokémon there are a few moves that have the same practical effect. Payback works like this - if your opponent hits you before the move goes off, you do double damage with it. Avalanche does as well. Fairly obviously, so does Revenge. There are also combinations that involve setting up a Desperation Attack (Flail and Reversal) to effectively function like this.
In Final Fantasy XII Revenant Wings, enemy leaders and yarhi/espers/whatever will often do this in battles involving Summoning Gates and Soul Crystals. Naturally, the group that had had the command to 'attack' will continue to follow the command, and chase after them if not intercepted quickly. If they are not intercepted then the group will end up in a trap of ever-spawning leaders or yarhi/espers/whatever from the Summoning Gate/Soul Crystal, and either fight until they die or get very injured/die while they escape.
In Warcraft 3 the alliance against the Burning Legion is simply intended to hold them off just long enough to set up a trap. Of course, given the odds they were facing, they weren't exactly letting them have it easy on purpose.
If you want to do well survive levels 1-3 in the Infinity Engine games (Baldur's Gate, Icewind Dale, etc.), learning this tactic will be a godsend.
Fate Stay Night: Archer favours these kinds of stratagems, employing them against Caster (using a slow-working attack and letting Caster think she has the upper hand before revealing that it's incoming) and Lancer (leaves intentional holes in his guard to turn dying from Death of a Thousand Cuts into an all-or-nothing defence, allowing him to stall for time until his strategic objectives are met). Rin also employs this against Caster (Letting Caster think she's won a magic duel before revealing she knows Kung Fu).
Often happens with Demomen or Engineers in Team Fortress 2. A Demoman will lay a stick bomb carpet somewhere, or an Engineer will put up a sentry, and then they'll go off and engage the enemy. If planned properly, they can simply retreat into the sticky bombs or the sentry and kill their opponent instantly.
This particular tactic appears explicitly at the end of ''Meet The Demoman," where the RED Demoman retreats from the charging BLU team... to lure them into a gigantic cluster of sticky bombs hidden just out of sight until it's too late. Cue Oh Crap, Stuff Blowing Up, and Ludicrous Gibs, in that order.
Scouts can also pull this off with a little practice: Run ahead of main force. Shoot enemy. Run back. Kill assist. Repeat.
Pyros, too. A common tactic when outgunned is to pretend to retreat and stop just around the next corner, flamethrower ready. Works best if the Pyro has managed to puff some flame at whoever is going to give chase before said chase starts.
A Spy with even a bare hint of height advantage can quickly turn a retreat into a Back Stab opportunity. This is known as an airstab or stairstab, as usually the path of retreat is up a flight of stairs, and jumping right back down behind the now-victim.
In Dragon Age: Origins, this is basically the entire battle plan for Ostagar: Lure the darkspawn into charging the main force, ambush them from behind. We'll never know for sure if it would've worked, thanks to Loghain having other ideas.
In Dynasty Warriors, the best ways to kill Lu Bu are power-leveling, and using this tactic to get him to follow you into your main base, at which point, a number of allied officers, and * infinite* allied mooks will bear down on him. Of course, he's still Lu Bu.
Wolfenstein 3D featured a level where opening a door would cause an army of Nazis to come at you from all directions. A sound tactic here (and all around the game) was to retreat to an earlier (hidden) room and, as the enemies followed you, open on them with a machine gun since they're conveniently bunched up and bottlenecked at the entrance.
In the Freelancer backstory, the GMG's main tactic during the 80 Years War was to lure the Rheinland ships into explosive gas pockets and other navigational hazards in the GMG's home nebulae.
Mogami Yoshiaki in Sengoku Basara has two moves, the first of which involves him standing idly while taunting, and the second falling to his knees and begging for forgiveness, only to attack with a Diagonal Cut the instant you touch him. Since it's impossible to defend and this will down your character for 10 seconds or more, it's best to just avoid him or use a ranged attack if you have one.
In Fallout New Vegas, this happened four years prior to the game at the first Battle of Hoover Dam. The NCR feigned retreat from the dam into the nearby Boulder City, sniping at the Legion commanders the whole way. Once they were in Boulder City proper, the NCR sprung the trap: they'd rigged enough explosives to level the town, and all the Legionnaires within it. And they did.
Thanks to Artificial Stupidity, it's possible to win battles without losing a single unit in Empire Earth. The AI will target only the attacking unit, so park your army close by, send an archer to fire a single arrow, then run it to the back. The AI's units will get slaughtered as they try to get at the archer. The most glaring example would have to be the Greek campaign, where Alexander the Great's army can basically win without a single loss.
In Danger By Design, Nancy defeats the villain simply by parrying one attack after another, until said villain (who's not much of a fighter) is too exhausted to continue.
A staple player tactic in XCOM Enemy Unknown, where it's commonly known as the Overwatch trap. Make contact with an alien pack in terrain that favors the aliens, fall back and set troops the aliens can't see in Overwatch mode. Works especially well on the more aggressive and less intelligent aliens, but it's not foolproof. Smarter aliens either won't fall for it or will just grenade where they think you are, while your own troopers can mess it up if they've been attending the Imperial Stormtrooper Marksmanship Academy.
An incredibly common tactic in Real Time Strategy games, against either an AI opponent or someone who doesn't micromanage very effectively: send out a small group/lone unit, drag back a portion of the army (preferably through a choke point) into your waiting defensive line. Move said line forward if possible, lather, rinse, repeat. This is especially effective in games that have units whose effective range is longer than their actual sight into the Fog of War; Terran Siege Tanks and upgraded Tau railguns made this both tactically and visually satisfying.
The dwagon-donut trick in Erfworld is a "defensive formation" example.
In Fans!, Rikk leads the crew in the "Python Strike" maneuver — running away. As it turns out, running away is the only "Python" part of it; the other part is laying the smack down on the pursuers.
In Second Empire, the immense First Empire task force invading Ziragalen gets the worst part of a Curb-Stomp Battle when their Glory Hound, General Failure commander fails to notice he's been led into a narrow gorge (filled with remote mines and snipers above) in his idiotic attempt to destroy the enemy leader personally.
From the superhero parody The Ripping Friends: A time traveler attempts to kill our heroes with their greatest weakness: Riptonite. Unfortunately for him, the Ripping Friends made this weakness up for the sole purpose of fooling overeager villains.