Respawning Enemies

""Infinite bad guys from a small door. Way to rip off the clown car.""

- Comic Book Guy, The Simpsons Game.

Hooray, you have managed to defeat the enemies that attacked you in this room. Don't get too cocky! Because when you return to this room later on, the enemies are fine and well again.

May even happen in games where levels aren't based on rooms, but set in one big area; in this case, the enemies respawn in a set position after a set period of time. Or possibly as soon as you move out of sight/attack range.

Respawning enemies come in several varieties:
 * Enemies that respawn within a certain time limit has passed.
 * Enemies that respawn every time room is reentered.
 * Enemies that respawn when they're scrolled off screen.
 * A rare variation is when enemies respawn when the game is saved, exited and loaded again.

Bosses are exempt from this. Bonus and other items usually don't respawn this way, unless something Randomly Drops, then you're expected to come back and fight the same enemy over and over until the Random Number God smiles in your favor. Availability of weak enemies obviously can help with Level Grinding. Conversely, their paltry Experience Points and junk drops may stop being worth the time wasted on constant running into them.

This could somewhat be a good to people who like to endlessly slaughter things or people who feel guilty about killing them.

See also Mook Maker - an entity that churns out enemies, and Enemy Summoner, who can do the same, but also is capable of attacking on its own.

Compare Puzzle Reset. Contrast Reviving Enemy, in which an enemy gets back up rather than replaced.

""Fifty thousand people used to live here, now it's an infinitely respawning bandit town.""
 * Halo: Combat Evolved approaches this, especially in the Library, especially on Legendary difficulty level. The Flood will eventually stop respawning but in some areas it takes a really long time and killing them all can take more ammo than you have available.
 * In the sequel, the Prophet of Regret and Tartarus both have respawning reinforcements.
 * Zool and its sequel, Zool 2.
 * The Nightmare difficulty in the Doom games has this as part of what makes it so hard, where any enemy that leaves a corpse would get back up after a random interval that could be anywhere from eight seconds to five minutes (usually closer to the former).
 * Syphon Filter games have this with specific opponents, which are known as "Magic Guards" to the fans.
 * Star Fox Adventures did this ridiculously often, usually only a few seconds after you'd defeated the enemies in the first place.
 * Every MMORPG with non-PvP enemies has this, naturally.
 * Guild Wars averts it though, no enemy will ever respawn while the players are still in the instance, and the entire game is instanced.
 * Xenosaga did this as well, though in varying amounts over the different games.
 * The normal monsters in Xenoblade Chronicles will respawn immediately if you warp to a different area, reload a save, or allow a large amount of time to pass. The stronger unique monsters can respawn in the same ways, but it's random, as opposed to guaranteed.
 * Alone in the Dark: The New Nightmare had plenty of monsters that would spontaneously regenerate when the player left the room and returned. Not too big a deal, until you find out that health and ammunition items don't self replenish. Ever. This serves as an outstanding example of why the Respawning Enemies trope is so rarely used in Survival Horror.
 * The Game Boy Color version of the same game did the same thing, but also sported Random Encounters. Since there are also no melee attacks and no way to flee monster battles, running out of ammunition during a fight renders the game Unwinnable.
 * Resident Evil Code: Veronica also does this somewhat, exacerbated by the scarcity of ammo.
 * In the Rune Factory series, the monsters are re-created every few seconds, unless you destroy the generators in each room.
 * Call of Duty 1 and 2 did this to a ridiculous degree, sometimes with odds as lopsided as ten-to-one, particularly during defense missions (i.e. guard this crossroads). The expectation is that the player will have to be aggressive in completing objectives. Turtling, or being pushed to the defensive, will always result in a stalemate at best, or being eventually overrun at worst.
 * Call of Duty: United Offensive, widely regarded as the best pre-Modern Warfare game in the series, is criticized for using this system.
 * Modern Warfare 2 went to great lengths to avoid this trope, and the dev team swore up and down that almost every group of enemies was finite, if only you had enough ammo to hold out. So when do finally give in to it during the Second Sun segment, it's highly amusing: Due to an EMP, helicopters are literally falling out of the sky. As soon as the sergeant tells you to "Get to cover!", the game begins aiming for you with a never-ending rain of Blackhawks, Hinds, and even Hornets. Keep your eyes on the sky and step lively.
 * Call of Duty Black Ops brought it back in various places. One of the most often (rightfully) complained about parts (other than the below mentioned Khe Sanh level) is the hallway at the end of Executive Order, where it seems the entire Red Army is hanging out somewhere behind a corner.
 * In the Khe Sanh level, this doesn't become a problem until you foolish try and play on Veteran. When attempting to descend the hill, all mooks begin to assault you. If, by the grace of God, you make it down the hill and into a bunker, be prepared to run out of ammo before advancing because there are 10-plus enemies that respawn continuously and consecutively. On top of that, the only way to advance is to kick (yes, kick) napalm barrels into the trenches. This wouldn't be a problem if the trench, filled with thousands of enemies, was not refilled with Vietcong shooting at you as you stand up to kick the barrel, an action you cannot avoid, if you wish to advance.
 * Roebuck from World at War, which also follows this trope, lampshades this; when under attack by infinitely-respawning Japanese soldiers, he may shout "Where did they come from?!"
 * Despite the Modern Warfare 2 example above, due to the major turnover at Infinity Ward, this trope comes back into effect in Modern Warfare 3.
 * Endless respawning enemies often occur in the Medal of Honor games, particularly Allied Assault, and the bridge level in Frontline. They usually spawn Behind the Black, but can sometimes teleport in in plain sight.
 * Being a similar game, Homefront sometimes uses infinite respawners. Not always, fortunately (they're often limited and run out after a few waves), but when it does it tends to stretch your willing suspension of disbelief - how, for instance, does a survivalist ranch house hundreds of people, all pouring out to replace their fallen as you snipe them from a nearby church?
 * Most 2D Mega Man games have enemies respawning the very moment their position is scrolled off-screen.
 * Mega Man X 7 is notable in this regard in that, if you stood around after killing a foe, the player could see it respawn right before them.
 * Also applies to the NES series of Ninja Gaiden. If you position yourself just right, you can literally see an enemy respawn after you killed it and can just stand around all day killing enemies that just keep coming.
 * Every Zelda game (and impersonator) uses respawning enemies, who can drop items. Generally they don't respawn until you go a few screens away and come back.
 * In the original The Legend of Zelda, it was possible to save yourself a lot of fighting if you knew that enemies only respawn if you kill all of them on a screen. If you killed all the enemies but one, it would stay like that for the rest of the session, making it a lot safer to walk through the rooms you've cleaned out.
 * Castlevania:
 * Castlevania: Lament of Innocence. Upon entering a room for the first time, you can't leave until you kill all of the enemies. They'll respawn eventually, but don't have to be killed, and Lament's control system makes it very easy to bypass them. On the "Crazy" difficulty level, not only are there more enemies, they respawn every time you enter a room.
 * In most, if not all, other Castlevania games, enemies respawn when you leave, then re-enter a room.
 * In Retro Mud enemies spawn after a certain timer, rather than when you leave the room. Usually allows for some banter in between farming.
 * Metroid does it immediately after leaving the room. Such mechanics may be referred to as "Metroid-style" when appearing in other games.
 * In the Prime series, at least, they don't respawn until you've moved at least two rooms away, and in some rooms will spawn in different places depending on which way you come in, as it would suck to have Shriekbats in your face as soon as the door opens.
 * Metroid Prime 3: Corruption has a room with respawning aerotroopers guarding an anti-air turret. To expose the turret's weak point, you must pull three switches on raised platforms, and the enemies can reset the switches. The only way to win is to ignore the enemies and do it as quickly as possible.
 * Metroid Fusion put a little explanation into this game mechanic, in that the bodies of dead enemies keep getting reposessed by more X-Parasites. In fact, if you don't gather the X-Parasite left behind after killing an enemy, it will do just that without waiting for you to leave.
 * Freedom Fighters will send in an armored car or transport helicopter to bring in new troops in some levels. They can be stopped by blowing up the bridge they travel across or their refueling pad.
 * In the System Shock games and their spiritual successor BioShock (series), enemies will reappear in previously cleared areas. This is a mixed blessing, as although you need resources to beat them, you can also get resources from them, as well as research them. Since this game is part RPG, this would be the equivalent of Level Grinding. It's also far less annoying than other games, since there are far fewer enemies in these areas when you revisit them.
 * There is one particular area in Bioshock where Spider Splicers keep respawning right after you kill one. They climb out of a dark hole in the ceiling that's inaccessible to the player.
 * In an odd BioShock (series) glitch,
 * ''Metal Gear Solid:
 * In Metal Gear Solid 2: Sons of Liberty: During a cutscene in the first part of the game, Otacon informs you that there are a little over twenty enemies on the tanker. No matter how many dozens or even hundreds of the bad guys you chew through and dump overboard, however, there are always more to take their place. Later in the game there's a similar situation where the enemy's forces are supposed to be low, and yet no matter how many you blow up, stab, or otherwise obliterate there are always replacement guards.
 * It should be noted, however, that Otacon is refering to the normal crew of the ship before it's attacked by the terrorists. Still, they seem to be too many soldiers for the takeover of a normal tanker.
 * Used in Metal Gear Solid 4: Guns of the Patriots as enemies in a few areas will constantly spawn, however there are places in the game that have a ridiculous amount of enemies spawn one after another that it can be mistaken that the whole game has it.
 * In MGS 1's Communications Tower, the enemy is on permanent alert until you fight your way to the top.
 * The rooftops in the original Metal Gear had infinitely respawning jetpack soldiers. When you recover your gear after being captured, it has a transponder planted in it that will constantly summon enemies until you discard it.
 * Wizardry 8 - not only your enemies respawn when you leave the area or go to sleep, they always "evolve" to match your level.
 * The final showdown against Wong in Stranglehold had the bad guy's men coming in waves every time that Wong was out of the room.
 * Geometry Wars is an example of the "period of time" version of this trope.
 * Many minor enemies in Little Big Adventure games respawn when you leave the scene and re-enter it. This can work for you, though, since the enemies often leave money/life/magic bonuses when killed.
 * In Aliens vs Predator for the PC, human and xenomorph enemies continuously respawn throughout the level, making it impossible to clear an area, and forcing the player to always be on alert for attack from all sides.
 * Star Fox Assault handwaves it with generators that will teleport in enemy reinforcements, and actually makes a point about airborne enemy presence being possibly overwhelming for your teammates due to this, so if you take too long, you'll have to take to the skies and shoot down baddies for a while. Unfortunately, a large number of generators can only be reached by foot or tank, making these levels a prime example of how the game didn't have enough air combat for the series.
 * EarthBound possess a unique respawn system where enemies would be arranged in a mostly random fashion as you traverse an area and would respawn in areas a short distance off screen. While it means that there is no limit to the amount of enemies in a level, it is actually a system that's heavily beneficial to the player. The obvious application being that it is very easy to grind when you want, but since the enemies were randomized each time you moved away from and returned to an area, you could /choose/ whether or not you encountered certain enemies or groups of enemies by waiting till you found a bunch you were willing to fight (or not fight).
 * Most monsters in the Klonoa series respawn extremely quickly. It sometimes takes only a second or less for a portal to drop off another enemy after you've destroyed the last one. This also serves as a handy Puzzle Reset, as you use enemies in jumping puzzles; it is possible, and occasionally required, to continuously grab and jump off a single constantly respawning enemy.
 * The first Baldur's Gate game had some areas with enemies respawning wherever the Fog of War was. While this might have been plausible in some games, BG had the player controlling a party of up to six characters, which allowed you to fully encircle one spot and then watch as fresh monsters seemed to appear out of thin air atop the corpses of their kin every time you brought a character back in range of the spawnpoint. Thankfully toned down quite a bit in the sequel.
 * Final Fantasy Tactics A2 uses this in a rather creative manner. In one chain quest, you have to kill a specified number of a specified type of enemy and turn them in to the apprentice chef to complete the mission. If all of the type of enemy you want to kill are not on the field, more will spawn in at regular intervals, provided the enemy party has room. If this is the case, you are more than welcome to kill the undesired type if it means getting the desired type to spawn. Some math skills are required, as you must turn in the exact number needed.
 * The Elder Scrolls II: Daggerfall. Every dungeon is a Clown Car Grave. It doesn't matter how many in-game days it took to spelunk any dungeon: soon as you leave, new tenants have already moved in.
 * Don't forget that being in a city while having a bounty causes infinite numbers of guards to spawn, each single one of them yelling HALT! HALT! HALT!
 * Certain levels in the Lego Star Wars games will keep sending squads of mooks after you until a certain goal is completed, be it building a path or killing the guy who keeps calling in the mooks.
 * This was kept up throughout the Lego series, and the one level in each game in which you can't stem the flow of infinitely respawning baddies is usually the most hated in the game: Defense of Kashyyyk (Lego Star Wars), Pursuing the Ark (Lego Indiana Jones), and A Poisonous Appointment (Lego Batman).
 * In the original Turok game, enemies (even dinosaurs) would be teleported right in front of you without any explanation.
 * In the sequel, enemies respawn when you die and respawn or return from a save portal.
 * Lampshaded in Dead Rising—when you kill what should have been the last zombie in the entire city, much less the mall the game takes place in, you get an achievement (the aptly-named "Zombie Genocider") and the Real Mega Buster.
 * Left 4 Dead does this, with the only enemy that doesn't respawn being witches (being close to Demonic Spiders themselves due to using a 1-hit-KO attack on the survivor that alerts them).
 * Most maps of Final Fantasy XII: Revenant Wings have this. This mostly just keeps it from being overly easy, but there are a few times where you can have difficulty killing them faster than they spawn.
 * In God of War, there is a segment in which you must push a cage up a slope while fending off infinitely respawning enemies. Getting hit causes you to release the cage, letting it slide back down the slope.
 * Averted in Gothic, where everything you kill stays dead. The world does get re-populated between chapters though.
 * A really bad offender is Dark Forces; after clearing out a room you can turn your back on the wall and a storm trooper will almost invariably spring into existence between your back and said wall. This is sort of OK until the game starts respawing enemies carrying concussion rifles, the shots of which are practically impossible to dodge and knock off 10% of your total hitpoints.
 * Wario Land The Shake Dimension had this on a per room basis in the huge levels.
 * Kingdom Hearts games have enemies that appear while fighting, but they aren't random; there's a set amount of enemies that will appear and then you'll have "cleared" the area. You need to go three screens away and come back to get them to reappear, except in Birth By Sleep, where it is only one screen.
 * Final Fantasy XII's enemies generally won't respawn unless you go several screens away and come back, but there are some lower-level enemies in each area that will indeed keep coming back.
 * Yoshi's Island had certain spots (usually pipes) where enemies will keep spawning unless Yoshi has six eggs. Their only purpose is to provide Yoshi with more eggs, and it's always an easy enemy like a Shy Guy. Boss battles usually also have infinite respawns for the same reason. As a bonus, these enemies were appropriately named in the players guide under a fake genus, Edibilus Boringus.
 * Golden Eye 1997, as mentioned in the intro. Example: the first Severnaya bunker level, where you will inevitably trip the alarm and have to fight endless waves of Elite Mooks to escape.
 * Mickey Mousecapade was especially cruel with this on levels where you have to backtrack. For example, jumping up to the next screen, only to fall back down into the previous room with all the enemies respawned, :lands on respawned enemy:, :dies:. Even the instant-death-on-contact minibosses respawned, which meant that you could get stuck in an Unwinnable situation if you missed the key in the castle.
 * Some enemies, such as Raiders, in Fallout 3 respawn after a few days if you kill them (as long as they are outside). Interestingly, if you enslave a Raider rather than killing him, he will never respawn.
 * You can also kill enemies and drag their bodies to a location that their enemies spawn, allowing for massive cross faction battles every time you re-enter that area.
 * Some animals and Feral Ghouls respawn after a few days in New Vegas.
 * Many rooms in Killer7 have one or two heaven smiles that keep teleporting in with a chuckle. Handy for collecting blood.
 * Banjo-Tooie had every foe respawning, save bosses. This was both a blessing and a curse compared to the previous game, as you had to deal with the mostly 1-hit-kill foes again and again, but it also meant Honeycombs were unlimited, unlike the prequel with limited foes on each stage and therefore limited life.
 * In Eternal Sonata, rid the area of Mooks, leave, and return.
 * In Super Mario Bros. 2, and probably Doki Doki Panic, as well, enemies respawn from Behind the Black as you move around. This can be helpful, as certain areas might easily be made Unwinnable otherwise.
 * In Etrian Odyssey, even the bosses respawn after a few days.
 * In Hello Kitty Online you just put enemies to sleep in the first place, so to respawn, they merely wake up.
 * La-Mulana has these. Considering that most of the enemies in that game are classified as Goddamned Bats and main character can get easily kicked back to the other screen, it can cause frustration quite frequently.
 * In Glider PRO, balloons, copters and darts are the only things you can shoot down with rubber bands. The moment one leaves the screen, either by reaching the edge or being shot down, it respawns after a fixed interval, or perhaps immediately.
 * In Monster Hunter, this will vary. Usually, enemies will not respawn. Sometimes, enemies will respawn for a pretty long time, but eventually stop. Rarely, they will never stop spawning, and there will always be multiples of them in that zone. This can be bad when the enemies in question are particularly dangerous or annoying.
 * In Monster Hunter Freedom Unite, the monsters that aren't on your kill list only respawn once (except Vespoid & Honrnetaur) and when you come back the third time, they're completely gone. If you're going for 'kill X number of Y' missions, they'll respawn in a different place (again, only once). Good thing to remember if you're trying to get rid of a very big annoying monster using a weak weapon.
 * Committing sufficiently violent crimes (or hopping the fence at the naval base) in Grand Theft Auto games will spawn an endless supply of enemies, until you sufficiently reduce your wanted level.
 * You can clear rooms in Vagrant Story, but if you come back a little bit later, they'll be occupied again.
 * The game tie-in for Avatar is particularly bad in this regard: You can clear a room, turn around, and find viperwolves or Na'vi where there was no way for some to get in...not to mention that the Na'vi and RDA forces are supposed to both be somewhat limited in size, raising questions about how you managed to personally kill or see the deaths of what should be a large fraction of your opponent's forces...
 * Enemies slowly respawn on individual Tartarus floors in Persona 3. The longer you stay on a floor, the higher the chance that red Shadows, the stronger type, will appear - handy for Level Grinding. Be careful, as staying too long makes the Reaper show up.
 * The Antlions are the only enemy in the Half Life series that do this. It gets to be an asset once they're on your side, especially since you may have developed such twitch reflexes by then that you wind up killing several anyway.
 * (possibly) Lampshaded in STALKER when people talk about ruins they keep clearing of bandits, who keep coming back. Also a similar clearance quest involving dogs.
 * As one person on a certain Image Board put it:


 * Generally Fur Fighters is quite good at avoiding this trope but one level, which was based in hell so it gets away with it, had Elite Mooks spawn all over the place while you avoid cannon fire from tanks and then destroy said tanks.
 * In Soldier of Fortune, making too much noise causes enemies to randomly "teleport in", sometimes in plain sight. The Unfair difficulty turns this Up to Eleven.
 * In Golvellius, enemies would respawn any time there were less than the maximum number of enemies on the screen. This actually worked to the player's advantage as you needed a lot of gold, which could be obtained from killing enemies.
 * Used in the Wing Commander games several times:
 * In Wing Commander III, in the final Behemoth defense mission, Kilrathi fighters respawn infinitely until.
 * In the final mission of the same game, the Strakha ace "Stalker" will respawn just before going to the planet until your final wingman is no longer present, to ensure you fly the final leg of the run alone.
 * In Wing Commander IV, an infinite number of Border Worlds bombers will spawn if you refuse the second opportunity to defect from Confed until the Lexington is destroyed.
 * One mid-game mission in Wing Commander Prophecy feature infinitely respawning Nephilim fighters. The goal not to kill them all, but to keep your fighter and the Midway alive until the carrier is ready to jump out.
 * Super Star Wars also has these, most prominently on the 3rd level, where you need to get to the top of the Sandcrawler. If you fall down, you will find that all the Jawas you have killed are there again, and even the various mounted guns on the side of the vehicle have been mysteriously repaired.
 * On the hardest difficulty of Duke Nukem 3D enemies will constantly respawn. The Starship Troopers Game Mod of it uses enemies that respawn on all difficulties.
 * Non-boss enemies in World of Warcraft eventually respawn, as do outdoor raid bosses. For normal outdoor enemies the speed is dependent on the number of players in the region, and in extreme cases can lead to people being assailed by the enemy they killed seconds earlier. Respawns used to be a major annoyance in dungeons after a wipe, but now the shortened length of dungeons has made it less problematic. Maruadon in particular had people get lost in there, die, then get lost again because with enemies respawning they could no longer tell where they'd already been. Rare spawn enemies operate on their own timers, which in the case of the much sought after and aptly named Time-Lost Proto Drake is erratic but very long.
 * A staple of Roguelikes, enemies can often be seen to appear out of thin air. In Nethack, however, it's actually possible to render monsters extinct by personally butchering (or simply causing the game to spawn) 120 of them.
 * Enemies in Seiken Densetsu 3 would respawn after your party moved two screens away. Nice if you need to backtrack a short distance after entering a dead-end room.
 * Prototype does this understandably as the in-game Manhattan very much downsized, therefore you'd run out of things to kill very quickly with your obscenely powerful abilities. Most of the entity regeneration occurs off-camera.
 * Structures are special in a certain way. They take a few minutes to reset after destroyed, but you must also be far away enough for the physical structure to respawn. If you stick around nearby, the structure will remain destroyed and not spawn enemies, but its area influence will reset and take effect, therefore Mooks that spawn in the influence will continue to do so.
 * Enemies in the Resident Evil series only respawn after a room's been cleared in response to story events, and even then almost always only when you have to pass through those specific rooms. It's pretty handy if you don't know where the game wants you to go: If you see monsters, that's probably where you have to go next.
 * Somewhat played straight in most remakes of the original game. Not only will zombies get back up if you don't blow their head off or burn their body, they will quite literally Turn Red, turning into dreaded Crimson Heads, which are much faster, stronger, and take many more hits. Luckily they don't get back up after going down a second time, but it is best just to avoid letting get up the first time due to the fact you don't even get enough ammo to handle all the enemies once.
 * The Kirby series is an interesting example. In most of the games, enemies will always respawn offscreen. This means that if you defeat an enemy, backtrack a little, then head back forward, the enemy will be there again. This has led to some interesting fan theories...
 * One old Sprite Comic even lampshaded this and used it as a plot point: when a friendly Waddle Dee sacrificed himself to save Kirby, Kirby brought him back by walking offscreen.
 * In Legacy of the Wizard, circles will appear at the spots where enemies respawn a few seconds before they do.
 * In Wario World, enemies respawn if you go offscreen from their spawn point.
 * In Nuts & Milk, Nuts could respawn in a few seconds after drowning in the water at the bottom of the screen.
 * In Burger Time, enemies respawn around the edges of the screen a few seconds after getting squashed.
 * In the Wii version of A Boy and His Blob, enemies that are important puzzle elements respawn shortly after being killed.
 * In Diablo II, enemies respawn when leaving the game and coming back. In online games, the map will also change. Both online and offline, what enemies appear in which area can change. Also of note is that bosses also reappear like normal enemies.
 * The Syphon Filter series has it's share of respawning enemies, which can sometimes be observed appearing via Enemy-Detecting Radar, but The Omega Strain is a noticable example, as every level has infinitely respawning enemies. If the player has a sharp eye, they will occasionally see enemies spawning out of thin air, which makes some escort missions exceedingly tough.
 * The Descent series has the purple-veined walls that spawn a wave of enemies when triggered by an Event Flag. On most difficulties, they stop producing after three or so waves, but on Insane starting with the second game, they can generate indefinitely.
 * In "collect the chips" levels of FHBG, the enemies respawn in a set order. This can be exploited to keep easier enemies on the screen.

Non-Video Gaming Examples

 * In The Hunger Games,  In Catching Fire, the Quarter Quell course sends fresh monsters at the tributes for one specific hour per day.