-> One. Just one. One red Snifit. In the '''entire game''', this is the only red Snifit. Seriously. What the hell?
--> -[[http://web.archive.org/web/20101224214455/http://progressiveboink.com/archive/redsnifit.html The Red Snifit: A Subconian's Search For Meaning]]

A video game trope: an enemy, just a plain old enemy that inexplicably turns up only once in the entire game. You wonder why the developers coded it; you wonder if it was partially DummiedOut. Sometimes it's just there to provide a special challenge for anyone trying for OneHundredPercentCompletion for the MonsterCompendium. Sometimes it's there because it exists to fit a unique circumstance in a level or sidequest. Whatever the reason, it's unremarkable in most respects except that it's just there the one time.

There are two types of this, broadly speaking: enemies who appear only once in an entire game, and those who appear a very few times in only a single level or screen of a game. For whatever reason, {{Metroidvania}} games seem prone to containing Unique Enemies. [[GameMod Mods]] and romhacks will often feature this enemy more often, especially if it has a good gimmick.

Please try to avoid listing minibosses and so forth here; these enemies are notable primarily because they're regular enemies who could by all rights turn up at various points in the game but don't.
----
!!Examples

[[foldercontrol]]

[[folder:ActionGame]]
* In Armored Armadillo's stage in ''VideoGame/MegaManX1'', there is exactly one batton (the bat-type enemy from the ''VideoGame/MegaManClassic'' series) among the newer, skeletal bats. It also has the unique property of dropping {{One Up}}s when killed most of the time.
* In ''VideoGame/MegaMan5'', there are two enemies that show up at the end of the first fortress stage that simply circle around Mega Man until you either enter the boss gate or shoot at them until they go away. They don't appear anywhere else in the game.
* ''VideoGame/MegaMan7'' has a few, especially in Shade Man's stage. In particular, there are werewolf enemies that show up in a few rooms, but only two of them are in a place where they can actually transform into wolves (the rest stay in their humanoid knight-like form).
* The third stage of ''JourneyToSilius'' has the PersonalSpaceInvader [[FanNickname known as]] [=HumpBot=], which fortunately only appears about four times, and is not seen in any other stage.
* ''Super C'', the NES version of ''Super {{Contra}}'', has a single grenade throwing [[{{mook}} enemy soldier]] that appears only once in the first stage and is never seen again in any other stage. In contrast, the arcade version has at least three grenade throwers in the first stage.
* In the NES version of ''VideoGame/PunchOut'', King Hippo is the only boxer without a HeadSwap.
* ''VideoGame/CaveStory''
** The Giant Jellyfish shows up on a single screen just to provide an Item Drop without the usual BossBattle. Oddly enough, you ''must'' kill it multiple times.
** ''Cave Story'' also has the mimic door and chinfish (mentioned in the closing credits as the "only one."), both of which appear once near the start but never again in the game. Basil, an invincible enemy that can one-hit-kill you, only shows up in the undamaged Egg Corridor (although it functions more like a deadly room feature than an enemy), and an exploding green cloud only appears in the ruined Egg Corridor. The Gravekeeper is another unique enemy of no greater significance. [[GiantMook Giant Pingon]] in the same area is also an unique enemy.
* Many enemies in PS2 {{Shinobi}} appear only in bossfights, and they're often a tiny flyer themed with the boss, including fire-breathing heads for [[PyroManiac Homura]], giant snakes for [[AnIcePerson Kurokuda]], laser-spitting masks for [[GiantMecha Yatsurao]], shikigami for [[spoiler: Ageha]] and sentient paper charms for [[BigBad Hiruko]].
* The arcade version of ''{{Contra}}'', on the hard and HarderThanHard difficulty settings, has a pair of scuba divers that jump out of the water and attack you with knives at the beginning of the game, and they are never seen again.
* ''StreetsOfRage 2'' has a number of regular {{Mook}}s that have names unique to their respective sprite-palette combos. Examples include a Joseph named "Talk" and a Donovan named "U-3". Killing such mooks will net juicy point bonuses (useful for racking up [[EveryTenThousandPoints extends]]).
* The NES version of ''VideoGame/TeenageMutantNinjaTurtlesTheArcadeGame''
** This turtle-riffic game had three unique enemies in one entire stage. The Shogun's stage had Robot Gorilla Ninjas, Robot Scorpions, and Robot Tigers that came to life out of door paintings. After beating these things they never show up again throughout the rest of the game.
** The snow level earlier in the game had some as well; the hopping mechs disguised as snowmen, snowball-throwing Foot ninjas, and an invincible snow plow.
** ''VideoGame/TeenageMutantNinjaTurtlesTheManhattanProject'' had most enemies that aren't Foot Soldiers or Stone Warriors have only a few appearances: electric mines partway through Stage 2's first half, the small helicopter drones from the Arcade and first cartoon only show up halfway through Stage 6, Stage 8 introduces small robot heads that shoot lasers at you, and that's only the tip of the iceberg.
** In ''VideoGame/TeenageMutantNinjaTurtlesTurtlesInTime'' penultimate level, Starbase, there is a robot moving up and down who fires lasers at you. It takes one hit to kill, and no more appear.
* The NES/XBLA version of ''VideoGame/BionicCommando'' has lots of these, including the the [[HelicopterPack helipack]]-equipped Barrier Soldiers in Area 5, the [[ThrowABarrelAtIt barrel throwers]] and [[AttackDrone Remote Control]] Soldiers in Area 6, the Mobile Cannons and Helicopters in Area 7, the blue [[MadBomber bomb-throwing paratroopers]] in Area 8 (even better, these are only found in the US and PAL versions), a red version of said bomb-thrower at the beginning of Area 2, and the Construction Soldiers in Area 11.
* The NES ''{{Film/Batman}}'' game has a red ninja waiting to attack you right before the first boss.
* LollipopChainsaw has the named zombies... while some are mini-bosses, most are just slightly stronger mooks. They give more experience and bonuses once killed.
[[/folder]]

[[folder:ActionAdventure]]
* ''Franchise/TheLegendOfZelda''
** In ''VideoGame/ZeldaIITheAdventureOfLink'', just before you fight the final boss battles you walk through a room with in which a giant 'Bot' will appear from nowhere above your head. Given by this point in the game you've learned to upthrust with your sword, and the thing can be broken up with one hit, it's surprising that it hasn't appeared any earlier.
** ''VideoGame/TheLegendOfZeldaALinkToThePast''
*** This game has a blimp-like creature that splits into multiple smaller enemies by the shore of Lake Hylia...and nowhere else.
*** In the same game, the Lynels from the [[VideoGame/TheLegendOfZelda first game]] appear as but one group of three at the top of Dark Mountain near Ganon's Tower.
** ''VideoGame/TheLegendOfZeldaLinksAwakening''
*** Takkuri, a large bird that divebombs Link and steals Rupees or items from him, is an enemy type in some games but a unique enemy in ''[[VideoGame/TheLegendOfZeldaLinksAwakening Link's Awakening]]'' and ''[[VideoGame/TheLegendOfZeldaMajorasMask Majora's Mask]]''.
*** From the same game is a monkey that lives in one tree on the beach and throws coconuts at you. Occasionally he also throws a bomb at you. In general he's useful to farm money if you have some time.
*** ''Franchise/{{Kirby}}'' also appears as an enemy in only two rooms in the Eagle's Tower dungeon.
*** The Key Cavern has a single room with green colored bomb-enemies that follow you instead of bouncing off the walls.
** ''VideoGame/TheLegendOfZeldaOcarinaOfTime''
*** The Composer Brothers, which are strange Poe-like enemies that only appear if you open their graves in Kakariko Graveyard. It's entirely optional, and are one of very few enemies to speak with you after being defeated. (However, they have some minor plot significance.)
*** The [[KillItWithFire Anubis]] enemy is only seen in one or two rooms of the Spirit Temple; the White Bubbles are only found in one room ''period'', and aren't even present at all in ''Master Quest''.
*** The Tailpasaran is only found in one corridor of Jabu Jabu's Belly.
** ''VideoGame/TheLegendOfZeldaMajorasMask''
*** There's a single [[UndergroundMonkey Blue ChuChu]] in one small room in the Great Bay Temple. [[spoiler:As like other [=ChuChus=] it poses almost no threat, but unlike other [=ChuChus=] it doesn't contain an item, its sole function is to be [[HarmlessFreezing frozen]] for use as a [[CraniumRide platform]].]]
*** ''Majora's Mask'' has one Peahat hidden in a pit in Termina Field; kill it for a Piece of Heart and you never get to fight another one. This wouldn't be so unusual had the previous game not featured numerous Peahats of the same type in similar areas.
*** Similarly, normal Poes are only found in one room of the Stone Tower Temple, and a solitary 'normal' (as opposed to Business Scrubs and Mad Scrubs) Deku Scrub enemy is found in the Swamp Spider House. Both of these were a lot more numerous in Ocarina Of Time.
*** ''Majora's Mask'' also has only two Eyegores, who have the odd distinction of being unique from ''each other'' - One fires lasers from it's eyes while the other doesn't.
** ''VideoGame/TheLegendOfZeldaTheMinishCap'' has a single Blue Tektite in its overworld.
** From the Forest Temple in ''VideoGame/TheLegendOfZeldaTwilightPrincess'' comes a lone medium-sized Skulltulla that dangles over a gap in one room. It is never seen anywhere else in the game.
** ''VideoGame/TheLegendOfZeldaPhantomHourglass'' had the Pols Voice, which only showed up twice in very specific places in the Temple of Courage. This trope is very common in Zelda games.
* ''VideoGame/{{Startropics}}'' Has Squidos, enemies that only appear in one room in the game. To top it off, they appear shortly after you acquire a teleport-kick SmartBomb attack, so you probably don't see them for very long.
* The ''Franchise/TombRaider'' games do this a lot, but then as it takes place all around the world this is a given. Most enemies, such as the Dinosaurs in ''Tomb Raider'' and ''Tomb Raider III'', Tigers in ''Tomb Raider II'' and the giant Statues in ''Tomb Raider III'' are fought frequently in single levels but nowhere else. There is, however, only a single Hammerhead Shark that appears in ''The Last Revelation'' that can't be killed as there's no underwater weaponry in that game, unlike the others.
[[/folder]]

[[folder:FightingGame]]
* There's an enemy named Mizzo in ''[[VideoGame/SuperSmashBros Super Smash Bros. Brawl]]'' that looks like a marionette in a tank. He's only seen once in the game in Adventure mode, but it has a trophy... that details just how there's only one of him in the whole game.
[[/folder]]

[[folder:FirstPersonShooter]]
* ''VideoGame/{{Half-Life}}'' series.
** In ''VideoGame/{{Half-Life 2}}'', the Claw Scanners appear in a couple of chapters and don't appear again until late in Episode 2.
** In the original ''VideoGame/{{Half-Life|1}}'', the Black Ops assassins only appear in two rooms in the entire game, and even then only in groups of three. In ''Opposing Force'', they're more common and have more variations, but only slightly so.
** The alien auto-cannon. One appears in one corridor in the original game, having been set up by Alien Grunts, and nowhere else.
** Game specific example: while common in the last levels of the original game, the Alien Controllers only appear once in ''Opposing Force''. Also, there is exactly one enemy Apache here, while in the original Half-Life, there were up to five.
** The Antlion Guardian in ''Episode 2''. Essentially a PaletteSwap of the the normal Antlion Guard, it's only encountered once in the entire game. While it is much stronger than normal enemy, it's not really powerful enough to be called a boss.
* ''Franchise/{{Halo}}''
** ''VideoGame/HaloCombatEvolved''
*** In only one room in the final level do you encounter cloaked Flood.
** ''VideoGame/{{Halo 2}}''
*** "Gravemind" had the "Honor Guard Councillor", which was actually a [[TheMissingno glitched]] Zealot Elite. This is the only Zealot fought on difficulties lower than Legendary. This is also the only level where Spec-Ops Elites appear as enemies.
*** "Quarantine Zone" has a single Sentinel that shoots with Needler rounds instead of the Sentinel Beam. According to one of the programmers, it was a rejected concept they forgot to remove.
*** "Cairo Station" has a pair of Elites dual-wielding plasma pistols at the beginning, an uncloaked Stealth Elite, and an Elite wielding both a Plasma Rifle and Needler at the end.
*** At the end of the underwater passage on "Regret", you encounter a group of stealth-cloaked Grunts, which are never seen again.
** ''Halo3ODST'' has an NMPD officer who turns on the Rookie because HeKnowsTooMuch on "Data Hive". This is the only time in the entire series that you have to fight a human enemy. "Data Hive" is also the only time in campaign where there are gold-colored Drones, who are apparently adolescent leaders.
** ''HaloReach''
*** In every level of this prequel, there is a special hidden Elite who will randomly appear out of nowhere in certain areas if you're fast enough in playing the level. These Elites, nicknamed "[=BOBs=]", give you a load of points when killed (to add to your credits if scoring is turned on) and a special medal if your Xbox Live account is linked to Bungie's site, but if you don't kill them fast enough they will disappear. [=BOBs=] come in two flavors: Gold Spec-Ops Rangers and completely white, random model Elites, similar to the aforementioned Honor Guard Councillor. The second variety's white coloration is due to a spawning error where the game "forgets" to add the correct color to the Elite character model.
*** There's one point early in the game where you fight a pair of King Kong-sized lizard-gorillas (referred to as [[http://halo.wikia.com/wiki/G%C3%BAta Guta]]), who are basically part of Reach's local wildlife. They're tougher than normal infantry, but not so tough that you could call them a boss battle or anything. They're never seen or heard of again afterwards, making the whole encounter something of a BigLippedAlligatorMoment.
*** Similar to the [=BOBs=], the first level contains a lone Stealth Elite (different color than the cloaked Spec-Ops Elites encountered later) nicknamed "Bill", which can be spotted just before the moas first appear. If killed, it drops a data pad that can be read. This also may be a leftover from a dummied-out objective.
* The first-person shooter ''Ubersoldier'' features a single flamethrower-toting, gas mask-wearing soldier in the final level. He can be killed quickly, and never appears anywhere else.
* ''SeriousSam II'' (the Xbox port at least) has exactly one ork (which has a different design) that use the plasma pistol as a weapon. It only appears in a secret arena of the sewer level.
* ''VideoGame/{{Marathon}}''
** In ''VideoGame/{{Marathon}} 2: Durandal'', the "[[KingMook mother of all Cyborgs]]" only appears once, on the level "Sorry Don't Make It So". In ''Infinity'', it became a recurring (but rare) enemy, and they were even more common in the ''EVIL'' GameMod.
** In the first ''Marathon'', the Drinniols were only used twice in the entire game, on "The Rose" and "Blaspheme Quarantine". They also had a DummiedOut orange PaletteSwap, which may have been the source of the "[[UrbanLegendOfZelda A Good Way To Die]]" SecretLevel rumors. Better yet are the hostile [[{{Attack Drone}} M.A.D.D.s]] with grenade launchers that only appear in one level, "Beware of Low-Flying Defense Drones".
** ''VideoGame/{{Marathon}} Infinity'' has several of these, due to its ability to use separate physics models for individual levels. For example, in Confound Delivery, there's a Juggernaut that fires bouncing grenades rather than the usual homing missiles. The Vidmaster's Challenge version of "If I Had a Rocket Launcher" is the only level to feature [=VacBOB=] [[ActionBomb Simulacrums]].
* ''VideoGame/{{Crysis}}''
** Only 12 enemy [[SuperpoweredMooks Nanosuit Soldiers]] appear throughout the entire game. While this somewhat makes sense from a storyline perspective (Nanosuits costs about 1 million dollars each), it's a bit underwhelming from a gameplay perspective since they're only about as tough as a [[{{Halo}} Covenant Elite]], so they could have easily been used more often without being unbalanced, especially in the later levels.
** There's a type of alien trooper that has a different head crest and is equipped with a freeze ray instead of an ice gun. There are only about 3 or 4 of them in the entire game. Again, they're a fairly standard enemy, so it's not like they make up for their rarity by being much tougher than normal or anything like that.
* In the 2009 ''VideoGame/{{Wolfenstein}}'', EliteMooks are ''extremely'' rare, especially when you consider that they're only slightly tougher than regular enemy soldiers. For example, there are only about 8 Elite Guards in the entire game, or only about 9 Flamethrower Soldiers in the entire game.
* The "Bouncer" Big Daddy enemy that serves as the mascot of ''Franchise/{{Bioshock}}'' is actually only fought twice; once on the second level and once on the final level. All other Bouncer-type Big Daddies encountered in the game are the Elite variant, which uses a different character model (though one can revisit the second level and fight more plain Bouncers).
* ''VideoGame/BioshockInfinite'' has exactly one Vox-Populi-aligned Handyman in the main game, all others belong to the Founders.
** There's also exactly one Sniper fighting for Slate's heroes, and one Sniper fighting for the founders. All others fight for the Vox-Populi.
* ''PathwaysIntoDarkness'', not including boss-type enemies, has the [[InvincibleMinorMinion invincible]] Green Oozes on "Warning: Earthquake Zone", the flying rats and flying lizards on "See in the Dark" and "Watch Your Step", respectively, and the [[InvisibleMonsters invisible Wraiths]] from A Plague of Demons and electrical orbs in the Labyrinth that are not seen again until the MultiMookMelee at the end of the game.
* Cassandra's BodyguardBabes seen during Mission 1-3 in ''PerfectDark'' and in the BonusStage "Mr. Blonde's Revenge". They make up a fairly large number of enemies in the former and are almost all the enemies in the latter, but otherwise are never seen.
* In ''{{Killzone}} 2'', only several [[EliteMooks Elite Shock Troopers]] are fought, all in the third-to-last level. In ''Killzone 3'' only ''two'' of these guys show up in the entire game, as part of the first wave of enemies at the beginning of the last level. It's entirely possible for your allies to gun them down before you even notice them. ''Killzone 3'' also has the Capture Troopers and Hazmat Troopers, [[BigBad Chairman Stahl]]'s personal elites who show up frequently in cutscenes but are only seen a handful of times in the game.
* ''VideoGame/Left4Dead2''
** The game occasionally spawns Jimmy Gibbs Jr. at the finale of Dead Center. He's basically a extra-tough version of the hazmat zombies.
*** Hazmat zombies are one of the "Uncommon" Infected that act as this - zombies that only appear in one campaign and have some attribute changed from normal zombies (aforementioned hazmat zombies are immune to fire, fallen Survivor runs away and drops items on death, clowns attract small hordes, mudmen move faster and blind players, workers ignore pipe bombs, and riot zombies are immune to attacks from the front).
** The first Tank in The Sacrifice looks different from the other Tanks in the game - bald and with the USMC logo tattooed on his chest where every other Tank has a rather large wound. There's otherwise nothing different from this one and all the others.
** The first level of The Passing is the only place where you will encounter the bride Witch.
* The first ''VideoGame/RedFaction'''s one-time non-boss enemies include the APC after leaving Mine M4, the Riot Guards in the barracks, the Ultor Combat Drone in the shuttle bay area, and the adult Rock Worm near the end of Capek's Zoo.
* ''[[VideoGame/DarkForcesSaga Jedi Knight: Jedi Academy]]'' has quite a few enemies that appear in only one or two levels, though a lot of them function more as bosses than as mooks. One of the most unique cases is a specific mercenary in the Nar Kreeta level, the only one in the game that drops a key on death (every other key the player needs drops from Imperial officers) and has the voice of a stormtrooper instead of the normal merc voice.
[[/folder]]

[[folder:{{Metroidvania}}]]
* ''Franchise/{{Metroid}}''
** ''VideoGame/SuperMetroid''
*** This game has a few in Maridia, mostly for functional reasons: In one corridor, a bizarre walker carves a path through a wall for the player. Later in the same segment, a corridor contains a squirming pile of white...things to help show off one of the abilities of Samus' new found equipment.
*** Maridia also has a large turtle-like creature accompanied by little baby turtles. Its purpose is to help reach a missile pack that would otherwise require Space Jump (which you only get later) to reach. There's also the mysterious orange Zoomer in crateria, which looks like a normal Zoomer exept it's orange, only appears in one room in a place you can't reach, and keeps following you around as you move. It can be killed with the Wave Beam, just as easily as any other Zoomer.
*** The Dachora and Etecoons can be saved at the end of the game by entering a side room and shooting the wall. No reason [[VideogameCaringPotential other than to help those who helped you]]. They actually appear again in ''MetroidFusion''.
*** The hallway just before Ridley has two "ninja" Space Pirates. The only other place they appear is during the escape sequence.
** ''VideroGame/MetroidPrime''
*** Ice Shriekbats are a famous one-time scan. They only appear in one room in the entire game, they look just like a very common enemy you've already scanned, and they disappear as soon as you get a nearby suit upgrade and never appear again, making it impossible to fill your logbook if you missed them. There are several other one-time scans in this series, too. Thankfully, this is changed in the PAL version.
*** There's also Ice Parasites that only appear in two rooms and disappear from the game, but luckily they'e not quite as easy to miss as the Shriekbats (for one, they don't fly at you and explode on your face as soon as you get close). Same with the Aqua Drones, which appear in one room and disappear after that.
** ''Metroid Prime 2: Echoes'' has the Lightbringers, which are living, walking safe zones that crawl on walls. Interesting game mechanic that could have been used in a lot of places... but no, you only got to see three of them in a room near the beginning of the game, and they're gone when you come back later.
** ''Metroid Prime 3'' has a frustrating few, including the [[ThatOneSidequest incredibly hard to scan]] gel ray.
* ''Franchise/{{Castlevania}}''
** ''VideoGame/CastlevaniaAriaOfSorrow'' has a couple of ordinary enemies who appear in just one room to frustrate OneHundredPercentCompletion, such as the super-fast flying fish enemy that requires a [=TimeStopper=] from ''another'' UniqueEnemy, the Chronomage, just to see and defeat. There's also the almost harmless Tsuchinko enemy, which is an in-joke on a Japanese cryptid/urban legend.
** ''VideoGame/CastlevaniaDawnOfSorrow'' also has a few unique enemies. Three are of the "special requirement to find" (Mothman, Winged Humanoid and Yeti) variety, and there are several others that just happen to have one spawn location in the entire game (such as the Alura Une and the Wakwak Tree).
** ''VideoGame/CastlevaniaSymphonyOfTheNight''
*** The Dodo bird, who appears in one room and runs for its life the moment it sees you...with good reason, too, as killing it gives you a chance at an InfinityPlusOneSword [[RandomlyDrops drop]].
*** Symphony actually has loads, especially if you consider enemies that appear more than once, but never outside of the one room they're found in.
** The dodo above re-appears in ''[[VideoGame/CastlevaniaPortraitOfRuin Portrait of Ruin]]'' in a single room... sometimes. It's pretty much random. There are also a few others. {{Sand Worm}}s in the desert levels only appear once and never re-appear once killed, and there are two palette swapped kinds. A ghoul king only appears after killing ghouls in certain rooms after a certain time, and the giant ghost only appears in a single room after killing ghosts for a certain time. Aside from the sandworms, they're required for sidequests.
** Oddly, the Stone Rose/Man-eating Plant which is fairly common in later games only appears in one spot in Stage 1 of ''VideoGame/CastlevaniaRondoOfBlood'', as well as the hunchback in Stage 3 who tries to steal your subweapon.
** The glass skeletons only appear in one room in ''VideoGame/CastlevaniaHarmonyOfDissonance''. They seem to be there to give nice exp. Also, the aptly-named Rare Ghost, which only has a 20% chance of appearing in one of a few rooms. It is entirely possible to go through the game without even seeing one. There's also a number of unique Armor enemy variants that only appear in a single room.
** Devil in ''VideoGame/CastlevaniaCircleOfTheMoon'', an absolutely ''vicious'' BossInMookClothing that can drop the best healing item in the game, is found only at the top of the Clock Tower and in the final room of [[BrutalBonusLevel The Arena.]]
* Most of the room-specific enemies in ''VideoGame/LaMulana'' are really minibosses, but there are a few exceptions: Thunderbird in Tower of Ruin, a large white thing that fires lightning downwards; Ba in the Confusion Gate, which looks and acts like a larger version of the GoddamnedBats ''La-Mulana'' players all know and hate; and Spriggan in the Chamber of Extinction's [[DisconnectedSideArea upper area]], a giant which the player needs to turn into a stepping stone to a higher platform.
[[/folder]]

[[folder:MMORPG]]
* ''WorldOfWarcraft''
** [=WoW=] has a few of these. In Utgarde Keep, you encounter several protodrakes but only one with a rider. Gundrak has the Drakkari Inciter, a weak enemy who only appears once in a group of two more common enemy.
** On a different note, Rare enemies (marked with a silver frame) only appear once every several hours (or randomly in instances) and are generally killed quickly since they drop very useful items.
** Most dinosaurs aren't (at least commonly) found outside of Un'goro Crater.
** There are extremely few shark mobs in the entire game.
** Undead Quilboar are only found in Razorfen Downs.
** Lord Marrowgar was initially the only Bone Wraith ever shown. As of Cataclysm, Marrowgar has received a brother bone wraith. Earthrager Ptah.
** Lord Rhyolith has a unique model in his first form, although his OneWingedAngel form in Phase 2 is shared by an add in the Amber-Shaper Un'Sok encounter in the Heart of Fear.
* In Videogame/{{EverQuest II}}, in the older zones more so than the newer ones, 'named' monsters would sometimes have a 'placeholder'. This placeholder doesn't usually have any unique abilities or loot drops, it's just a mook with a unique name.
[[/folder]]

[[folder:PlatformGame]]
* ''Franchise/SuperMarioBros'' has quite a number of these:
** In ''VideoGame/SuperMarioBros1'', World 7-3 is the only level with flying green Koopa Paratroopas (though the bouncing ones are found in other levels, such as 8-2).
** The single Red Snifit in ''VideoGame/SuperMarioBros2'' (which shows up in one room of 3-3) was the former TropeNamer. Got [[http://www.progressiveboink.com/archive/redsnifit.html its own page]].
** ''VideoGame/SuperMarioBros3''
*** The shoe-wearing Goombas appear only in World 5-3 of ''VideoGame/SuperMarioBros3''.
*** The game has also the Spiny Cheep-Cheep and a lone ''fire-breathing'' Nipper (both found in World 7).
*** The Parabeetles are only found in one level of World 5. It seems they were planned to be in more levels, according to the screenshot of a deleted level on the box. There's also a green version in some of the DummiedOut levels.
*** The Fire Brothers are only encountered in a secret part of the World 2 map, carrying the third Warp Whistle, and as a solitary individual in one of the Hand Trap stages in World 8.
*** The laser statues in Bowser's Castle.
*** The Angry Sun in an unnumbered stage of World 2 and World 8-2.
** ''VideoGame/SuperMarioWorld''
*** The game has one level with a Lakitu that taunts you with a 1-up mushroom on a fishing pole. Despite its rarity, the fishing pole has since become an IconicItem for Lakitus in spinoff games, most notably ''VideoGame/MarioKart''.
*** There's also the Fishin' Boo, a rare ghost Lakitu that follows Mario with a flame on a fishing rod. It only appeares for a short while in the first room of the Choco Island Ghost House. The same stage also has a few ghosts that turn into solid blocks when Mario looks at them.
*** The Torpedo Teds of the Soda Lake level. It's a hidden level too (which leads to Star Road), so it's likely the first time you'll see them is in the ending roll call.
*** Each alternately-colored Yoshi appears in only one or two Star Road levels. (You ''can'' turn any Yoshi blue in the SNES version if you find Yoshi Wings.) The Game Boy Advance remake changed this so that after you unlock them at the Star Road, the Yoshi Eggs can be any of the four colors depending on what powerup held at the time.
*** ''VideoGame/SuperMarioWorld'' also has the Ninji enemy from ''VideoGame/SuperMarioBros2'' show up only in the last hallway of Bowser's Castle. There are also Mechakoopas in this last level, seen in one of the selectable paths, in the aforementioned last hallway, and during the final battle.
*** The random Bullet Bill generators that are in a few of the later athletic levels of the original ''VideoGame/SuperMarioBros'' return in ''Super Mario World''. There is actually a ''diagonal'' variant of the generated bullets in this game, but it appears only in one sublevel of Cheese Bridge Area. Said sublevel is not only a mere 4 screens long but contains no items of any kind, so unless you take an exceedingly long time getting across the moving platforms, it's not terribly unlikely that you'll see the bullets fire once the first time playing the game and then never again. In fact, there are ''three'' different variants of these generators in this game: the aforementioned, the basic horizontal ones, and one that spawns two horizontal and two vertical bullets. ''All'' of them are rare and rarely seen; the other two appear only in Vanilla Dome 4, the horizontal one in the first half of the level and the multi-directional one in the second half, and a quick player can actually bypass the latter entirely (making use of the bonus room to skip part of the level).
*** Also from [=SMB1=], the flying Cheep-Cheep generator is MUCH more aggressive in this game...but it is only ever seen in about 7 screens of another bonus level, and most players will probably have taken the [[InvincibilityPowerup Starman]] to deal with them easier anyway.
** ''[[VideoGame/YoshisIsland Super Mario World 2: Yoshi's Island]]''
*** This game provides many examples that appear in only one castle or fortress stage. Georgette Jelly is exclusive to 5-4, Lemon Drops are only ever seen in one room of 3-4 (aside from the one Lemon Drop that Kamek enchants to create the boss of 1-8), Aqua Lakitu is found only in a side path of 3-8, Piro Dangle is found only in one optional room in 1-4, the 32x32 variant of the Milde enemy is never seen outside of a secret room in 4-8 and the 4-4 boss battle, and one room of 5-8 contains the only Bouncing Bullet Bill Blaster in the game. Grim Leecher is found only in a couple places in Extra 4. Yoshi's Story is similar, with enemies like Blindfold Boo and Barbecue Guy only appearing in one stage. Because all bosses in Yoshi's Island are of the GiantMook variety (after a MakeMyMonsterGrow sequence), many are based on enemies that appear in the boss's level (long enough to "establish" them as monsters) and nowhere else.
*** As a bit of an Easter egg, killing the one and only Chain Chomp in ''VideoGame/YoshisIsland'' (which requires the use of an item, since he can't be eaten, stomped, or killed with an egg) reveals a hidden message block.
*** The level 'Monkey's Favourite Lake' has Barney Bubble, a strange purple creature that blows bubbles when you stomp on it. Only two appear at the very end of the level and nowhere else.
*** And Muddy Buddy, which only shows up once in 5-4. It does appear in one of the secret levels added to the GBA version.
*** [[GiantMook Gargantua Blargg]] only appears once in both Yoshi's Island and Yoshi's Island DS (not counting the taller Crusher Blarggs from the latter) but three appear in two levels in Yoshi's New Island. Similarly, Hefty Goonie only appeared once in the original, but it appears in at least three levels in Yoshi's New Island.
*** Also on the subject of the GBA version, Secret 6 has red Bullet Bill blasters whose bullets will home in on Yoshi while biting their teeth and disappear after a while. This enemy is fully coded in the SNES version, but it never shows up at ''all'' in that one.
*** In ''Yoshi's New Island'', it's easier to list the enemies that aren't unique to one stage. For example, outside of a single hiding Bandit in 5-3, you'll only encounter them in 6-2, there is only one Whirly Fly Guy tucked in at the end of 1-3, Woozy Guys and Caged Ghosts only appear in 3-8 (the former being spat out by the latter), and the flying Skeleton Goonies only appear in an optional hot air balloon section in 6-7 and outside Bowser's Castle in 6-8.
** ''VideoGame/SuperMario64''
*** In Cool Cool Mountain, on the longest bridge, there are two Jumping Snowmen, which appear nowhere else in the game.
*** This platforming adventure includes a [[AttackOfTheKillerWhatever killer piano]] in Big Boo's Haunt that attacks when you get near it and can't be killed.
*** Hazy Maze Cave is the only level to contain Swoopers.
*** And a solitary Chain Chomp in Bomb-Omb Battlefield which you must set free to get a star.
*** Within Lethal Lava Land, there the only two Big Bullies, both of which contain a power star.
*** Bubbas (large fish that will eat you) are only found in Tiny Huge Island, on the Huge Side.
*** The Tox Boxes, Pokeys, Grindels/Spindels and Klepto the Condor only appear in Shifting Sand Land.
*** On an icy arena within Snowman's Land, there lies the only Chill Bully. He is identical in every way to Big Bullies, other than visually.
*** In ''SuperMario64DS'', the only Manta Ray, Shark, and two Cheep Cheeps in the entire game appear in Dire Dire Docks, at the very beginning, near the whirlpool.
** ''VideoGame/SuperMarioGalaxy''
*** The lone Grand Goomba, which is too big to jump on.
*** ''Galaxy'' also features only two giant jellyfish enemies in the whole game. Only one appeared in ''VideoGame/SuperMarioGalaxy2''.
** In ''VideoGame/SuperMarioGalaxy2'', there are quite a few examples in the game. Among others, there is only one Spiky Piranha Plant at the end of Sky Station Galaxy's second stage, a single Jammyfish in the middle of Cosmic Cove's second mission, Cluckbooms, Pokey Sprouts, and Rhomps only appear in the first mission mission of Slipsand Galaxy, and Kleptoads only appear in a Hungry Luma planet in Hightail Falls Galaxy.
** ''VideoGame/NewSuperMarioBros'' series
*** The King Bill appears in only one level each in ''VideoGame/NewSuperMarioBrosWii'' and ''VideoGame/NewSuperMarioBrosU'' (9-8 and 5-Secret, respectively).
*** Also appearing in only one level: the Fliprus from the latter game, giving 4-Secret its name and not showing up in any other levels.
*** So far, there has only been one [[VideoGame/SuperMarioWorld blue shelled Koopa]] in the entire ''New'' series, and it's not even in a main game: It's found in the ice-themed multiplayer stage of [[VideoGame/NewSuperMarioBros1 the first game]].
*** In the game ''VideoGame/NewSuperMarioBros2'', the only Sledge Bro appears in level 2-2.
*** And even in [[VideoGame/NewSuperMarioBros its DS predecessor]], the only level where Sledge Bros. and Fire Bros. show up (two of each) is 8-7. Three Sledge Bros. are in ''VideoGame/NewSuperMarioBrosU'', all of them in the World 7 castle.
** ''SuperMario3DWorld'' has a few, most notably the Charvaargh, which shows up only in the final section of one of the later levels. There is also the Fuzzler, which is exclusive to 3-7. Cheep-Cheeps and Porcupuffers only appear in 3-5. Brolders are found only in the fourth castle stage and a couple of enemy blockades.
* ''VideoGame/{{Kirby}}''
** ''[[{{Kirby}} Kirby's Dream Land 3]]'' has two instances. The first is Polof, a rabbit-like creature that appears in one level of Sand Canyon, and disappears into a background wall when you approach. Though this one actually has a purpose: [[spoiler:That spot where it vanishes is a secret door leading to a room filled with items. The Polof is still missing, though.]] The second is Batamon, which appears in a few levels and looks a lot like Kirby. Usually there's no way to engage them directly, though in one level there's a secret where you can. There are also certain copy abilities that'll let you destroy them from a distance, but there's no discernible reason to do so.
** ''[[VideoGame/Kirby64TheCrystalShards Kirby 64]]'' also has the waddling grey enemies, N-Z. They serve as a replacement for the Waddle Dees in the rest of the series (since Waddle Dee is a friend now), and are all set up to be the game's [[TheGoomba Goomba...]] ...and then they don't appear anywhere in the game outside of the first level, and the very last section of the last level.
** In Kirby's Adventure, Rolling Turtle (Phan Phan in the remake) is only found in level 4-4. The only other time you find it is 7-2, which is a [[BossRush Miniboss Rush]] level.
** Kirby and the Amazing Mirror has a single Squishy tucked away in a water-filled area in Moonlight Mansion.
* ''VideoGame/WarioLand: Shake It!''
** Buccaneros only ever appear '''once''' in the tutorial level... and maybe very rarely late in the battle with Large Fry.
** Also, the [[ChestMonster evil treasure chests]] that eat Wario only appear three times in the level Boogie Mansion, are blasted open to get treasure, and don't respawn.
* Every level in ''VideoGame/WarioWorld'' except for Greenhorn Forest has at least one enemy unique to it.
* ''Many'' examples in ''VideoGame/DonkeyKongCountry 3'', often serving as a level's gimmick (However, most of these enemies are seen more than once in the Game Boy game ''Donkey Kong Land 3'', which is based off of [=DKC3=]):
** Bazza the barracuda shows up in only one of the game's many underwater levels, serving more as barricades to bypass than enemies. The Game Boy Advance remake includes them in some bonus levels, however.
** The bird enemy Swoopy serves a similar purpose in one of the game's bonus levels. However, you can find just one other Swoopy in one of the early tree-themed levels.
** Lemguins appear only in the last level of K3, popping out of holes and sliding towards you.
** Karbines serve as indestructible enemies in the first factory level, hiding in the background while shooting fireballs at you. Similarly, Krosshair from Krack Shot Kroc does this, except from the fourth-wall side of the screen. Although you play as Krosshair in one of that level's bonus stages.
** Kuchuka is a purple barrel that chucks bombs at you, appearing only in the level Pot Hole Panic.
** Pink versions of the enemy Koin show up in one of the levels in the last world, attempting to push you off ledges with their trash-can lid shields.
** Minkeys--little monkeys that chuck notes at you from behind barrel-shields--are only seen in one of the second world's levels though, like Bazza above, they made an additional appearance in one of the remake's extra levels.
** Gleamin' Bream, whose only purpose is to light up dark areas, in "Floodlit Fish".
** ''Finally'', the remake adds in a ground-based version of the TNT barrel Klasp to one of the new levels, which act similar to the Klobba enemy.
* The original ''VideoGame/DonkeyKongCountry'' had the Rockkrocs in "Stop & Go Station", and the almost completely invincible gray Krushas in "Platform Perils".
* ''Donkey Kong Country 2: Diddy's Kong Quest'' had:
** The [[InvincibleMinorMinion invincible]] Snapjaw, found in RiseToTheChallenge levels "Slime Climb" and "Clapper's Cavern".
** The Cat-O-9-Tails, which appears in only three levels, one of which has to be unlocked.
** The rollercoaster riding Klank in "Target Terror" and "Rickety Race".
** [[NightmareFuel Kackle]] from "Haunted Hall", another MinecartMadness level.
** The ghostly Mini-Neckies that show up during the Kreepy Krow boss battle.
** The faster, [[RealMenWearPink pink]] Krunchas found in "Castle Crush" and "Clapper's Cavern".
** The black variation of the Klobber only appears in Black Ice Battle and Chain Link Chamber. When they bump into you, they take lives from your inventory.
* ''DonkeyKong64''
** The Killer Tomatoes. They only appear in one specific area of Fungi Forest, and after you kill them, they're gone for good. The toy-themed enemies in Frantic Factory are also very rare.
** There's also the unnamed, clam-like monsters that are found in a treasure chest only Tiny can enter in Gloomy Galleon, and the Red Kritters that only appear in minigames.
** The beaver creatures are basically TheGoomba for this game. However Crystal Caves is the only place you can find them with yellow fur.
* The Politician, a GiantMook fought at the end of Level 6 in ''VideoGame/PrinceOfPersia1''. This isn't technically a boss, as he is only slightly tougher than the regular {{Mook}}s. He was made into a proper boss in the SNES version, and replaced by the tougher Gatekeeper boss in the XBLA remake.
** The first enemy of Level 8 also qualifies. He looks like every other guard but has different AI. Including the fact that he'll never move towards you, so you really have to learn how to step forward and parry.
* The NeoGeo platformer ''Top Hunter'' has two unique enemies in the wind stage: a Tatoo guy who dies in one hit and a walking detonator that will eventually go away if you ignore it.
* Many enemies in ''VideoGame/MrGimmick'' are encountered only once.
* Two Klobbers, which debuted in ''VideoGame/DonkeyKongCountry 2'', make a random appearance in one level in ''DK: Jungle Climber''.
* Lots of things in ''VideoGame/IWannaBeTheGuy'' only show up in one particular place, usually to punishing you for a completely logical action with a BigLippedAlligatorMoment. These include [[StreetFighter Ryu]], [[MarioPaint a plane]], and [[VideoGame/SuperMarioBros2 the Red Snifit himself]], armed with a BFG.
* The 8-bit version of ''[[VideoGame/SonicTheHedgehog Sonic the Hedgehog]]'' has two enemies that each only occur once: Burrobot, in Labyrinth Zone, and Bomb, in Sky Base Zone.
* In Mick and Mack: Global Gladiators, there is one single skunk enemy in the second level.
[[/folder]]

[[folder:RailShooter]]
* ''[[TargetTerror Target: Terror]]'''s Tanker level has a pair of ninjas with nunchucks that deflect your bullets, which are found nowhere else in the game.
* At the end of the first stage of ''TimeCrisis II'', after the semi crashes, a group of gray soldiers with rocket launchers attacks you. Nowhere else do the gray soldiers wield rocket launchers. Also, during the first BossBattle and nowhere else, there are Aqua Ninjas that periodically jump out of the water. The first game also had knife-throwing guards during the DiscOneFinalBoss battle, which became recurring enemies in later games.
* In the default second level of StarFox64, there's a two-legged robot enemy that jumps up and down on an asteroid, shooting lasers at you (Nintendo's official guide calls it a "Hop Bot"). You shoot it. It dies. Never seen again.
[[/folder]]

[[folder:{{Roguelike}}]]
* In ''NetHack'', shades and skeletons are moderately-powerful undead who only appear on the level dubbed "Orcus Town".
[[/folder]]

[[folder:RolePlayingGame]]
* ''VideoGame/{{Mother 3}}''
** The game has Negative Man, a rather unremarkable and comically-underpowered JokeCharacter enemy who has a rare drop.
** He's just the most well known. There's also Fish Roe Man, Soot Dumpling, Mystery Metal Monkey, Bright Smile, Top Dogfish... There's nearly a dozen more with completely unique sprites that many players may never see hidden in the game. Mother 3 lives this trope.
* Several times in the ''VideoGame/{{Fallout}}'' series, even if they're basically just reskins or renames of vanilla {{mook}}s.
** ''VideoGame/{{Fallout 3}}''
*** At the bottom ''VideoGame/{{Fallout 3}}'''s Vault 106, you encounter an apparently non-insane Survivor who has the same voice and model as the Raiders, but wears a labcoat and is equipped with a Stealth Boy.
*** ''Mothership Zeta'' has only two Experimental Drones, who in turn carry the only two copies of the EX-B Drone Cannon.
*** The ''Broken Steel'' Mobile Base Crawler contains the sole Enclave Doctor in the game, who doesn't even fight back, only flees.
*** There is only one living female Talon Company Merc in the game, in the bunker of Fort Bannister. All other female Mercs are found as corpses.
** Radroaches are incredibly rare in ''VideoGame/FalloutNewVegas''. Which is odd, since they were the GoddamnedBats of Fallout 3. But [[SarcasmMode fear not]], the Giant Mantis is here to take up the mantle.
** ''Fallout New Vegas'' also has:
*** The Nightkin Sniper on Black Mountain, who, contrary to its name, does not wield a sniper rifle, but the unique missile launcher [[ICallItVera named Annabelle]].
*** Three LittleGreenMen aliens found near a crashed recon craft similar to the one from ''Mothership Zeta'', and only if your character has the Wild Wasteland trait.
*** The two Unnaturally Large Sized Rodents in the East Central Sewers, which otherwise have the same stats as normal Giant Rats.
*** The Giant Evolved Centaur in the Devil's Throat.
*** In ''Lonesome Road'', the optional [[BonusDungeon Courier's Mile]] is the only place where Irradiated Marked Men can be found. These have much higher HP than the normal Marked Men, and an enhanced HealingFactor thanks to the high radiation.
*** The female Lobotomites in the X-8 Research Center from ''Old World Blues''. Once killed, these do not respawn, unlike the randomly spawning male Lobotomites.
*** The three White Legs Sappers in ''Honest Hearts'', who only appear during the sidequest "The Treacherous Road".
* [[Franchise/SuperMarioBros Mario]] [=RPGs=]
** ''VideoGame/SuperMarioRPG''
*** This RPG has the Ribite, a PaletteSwap of the Frogog fought in the first world. It's found only in a hidden cave in Land's End, the fifth world... On top of that, it doesn't appear on the field screen either.
*** A creature called Drill Bit (a recolor of an earlier enemy named Jabit) appears after beating Smithy's first form as an NPC, and nowhere else (they apparently just started production on them when Mario and co. invaded The Factory).
** The weird flying jellyfish-like creatures ([[AllThereInTheManual named only in the manual as "Sentinels"]]) that patrol Tubba Blubba's Castle in the original ''VideoGame/PaperMario''. They can't be fought, and only act as {{Mook Bouncer}}s.
** ''VideoGame/PaperMarioTheThousandYearDoor''
*** In ''VideoGame/PaperMarioTheThousandYearDoor'', there is a type of Yux that you only run into once, guarding Grodus's office; it is by itself in the room and doesn't respawn.
*** There's also the Atomic Boo in the Creepy Steeple although it's a little GuideDangIt on how to get the thing to appear thus confusing many who saw it in the credits.
*** Some of the enemies in the Glitz Pit and Pit of 100 Trials.
** In ''VideoGame/SuperPaperMario'', most of the space enemies are justifiably never seen outside of Chapter 4. The eel-like creatures are, however it's implied they could basically live anywhere.
** The Elite Goombule of ''[[VideoGame/MarioAndLuigiBowsersInsideStory Mario & Luigi: Bowser's Inside Story]]''. Only two are ever encountered, directly after unlocking the Green Shell attack. The Player's Guide doesn't even bother listing them in the Enemy Compendium.
** ''VideoGame/MarioAndLuigiDreamTeam'' has a single Monolift R roaming around the Untibed quest-section of Mount Pajamaja. On the one hand, it ''does'' respawn if you kill it (but only after defeating a specific amount of other enemies each time, which is why they have [[AchievementSystem Expert Challenges]] connected to them like more common enemies). On the other, the only other enemies in the area where you can find it are [[VideoGame/DrMario Viruses]], which are only [[ActuallyFourMooks joined in battles]] with other Viruses.
* Throughout the ''Franchise/{{Pokemon}}'' series, there have been several non-legendary species of which only one is available to the player, whether in the wild or through NPC interaction. Notably, some of these species become more common in later Generations.
** [[VideoGame/PokemonRedAndBlue Generation I]]
*** The three starter Pokemon (Bulbasaur, Charmander, and Squirtle) can only be obtained from Prof. Oak. Other unique species include the three fossil Pokemon (Kabuto, Omanyte, and Aerodactyl), Snorlax, Farfetch'd, and Lapras.
*** In Yellow, Pikachu is your starter, and cannot be encountered in the wild.
** In the [[VideoGame/PokemonGoldAndSilver Johto games]], there's exactly one Sudowoodo you can fight. Snorlax is a UniqueEnemy again as well, this time with only one instead of two, [[ContinuityNod since Red has the other.]]
** [[VideoGame/PokemonRubyAndSapphire Generation III]]
*** [[GuideDangIt Bagon are only found in one room in all of Ruby/Sapphire/Emerald, and Feebas are only found in certain spots in one river.]]
*** Chimecho is notable for not appearing ANYWHERE else in the game, aside from a single floor of a tower that the player is unlikely to spend more than a few seconds on.
** This could be applied to some of the trainer classes as well, such as the two (and only two, period) police officers in the second generation and their remakes, which can't be challenged to a rematch, and Game Freak game designer and programmer Shigeki Morimoto has a CreatorCameo in ''VideoGame/PokemonBlackAndWhite'' with the unique class of GAME FREAK, [[CaptainObvious named after his employer]].
** [[VideoGame/PokemonXAndY Generation VI]]
*** [[OurFairiesAreDifferent The Flabébé line]] appears with serveral different colored flowers, depending on where you caught it. [[spoiler:[[WhoWantsToLiveForever AZ]]]]'s [[MoralityPet Floette]], however, is completely unique, having both a different colored body (which is always the same on a player-caught Floette), and flower (both in color and shape).
* ''VideoGame/{{Xenosaga}} Episode I'' has the Wyrm enemy, which only shows up once during the [[spoiler:Gnosis attack on the Foundation]], cannot be refought, and tends to flee.
* ''VideoGame/{{Xenoblade}}'' tends to have a few "Notorious Monsters" per questing area. They tend to look exaclty like certain creatures from that area, but with buffed-up stats. Oh, and when you fight them, one of the [[CrowningMusicOfAwesome best songs in the game]] starts to play...
* ''Franchise/FinalFantasy''
** Neo Garula from ''VideoGame/FinalFantasyV'' counts, as it can only be encountered once in the game (and even then, not guaranteed).
** Sp Forces/Imperial Elite in ''VideoGame/FinalFantasyVI'' only appear if you agree to test your strength against Gestahl's bodyguards during the banquet scene.
** ''VideoGame/FinalFantasyVII'' has a fair number of them all over the place. Although many are [[PaletteSwap palette swaps]], special mention should go to the unique Elfadunks and Heavy Tank. Elfadunks are tiny elephants found [[FridgeLogic only on the beaches]] near the Chocobo Ranch, somewhere you'll never need to go. Heavy Tanks are found only in a single screen near the Gongaga Reactor, but at least you can find [[SummonMagic Titan]] there.
** ''VideoGame/FinalFantasyVIII'' has enemies called Slappers, monsters in hockey gear that only appear on the hockey court in Galbadia Garden. They don't even get a trading card.
** ''VideoGame/FinalFantasyXII'' has quite a few.
*** The 80 rare game are exactly that--rare. Generally there is only one zone in the game they will spawn in, they will only spawn one at a time, and they have varying spawn conditions, ranging from simple ones like "30% chance on zone entry" to ridiculous ones like "spawn separate monster, aggro it, lure it to completely random and unmarked part of the map, and rare game will spawn." As for respawning them, a few simply require the normal monster respawn and then fulfilling their spawn conditions again, some require you to leave the entire area and return before you try again, and thirty of them ''do not'' spawn again. You kill them, that's ''it.''
*** The Elementals and entites operate on the same principle.
*** Then there are simply enemies who are completely normal, but for whatever reason, there's only one spawn point for them in the entire game--prominent examples are the Darkmare in the Stilshrine of Miriam, the Emperor Aevis in Paramina Rift, and most infamously, the Giza Plains Wildsnake. Weakest of the snakes, does not spawn until you get to its hiding point, completely unremarkable to fight--and its drop is required to [[ItemCrafting make]] the InfinityPlusOneSword.
* In ''VideoGame/SuperRobotWarsW'' there's a variation of [[{{Robeast}} Beastman]] [[GoLion Deathhell]] that only appears in chapter 25 (And only one of them, surrounded by several normal ones). What makes him so special? Instead of having his DualWielding attack, his Nipplebeams have a really high range. While it makes sense to face a sniper enemy on this chapter (The hero team is trapped in the Space Wolf planet's high gravity and thus can't move, leaving them unable to escape long-ranged attacks), this super-Deathhell is never referenced in dialogue and there isn't a need for him to exist (The battleships do his job fine).
* One room in ''VideoGame/ChronoTrigger'''s Black Omen is the only place you'll ever meet four Aliens (Ghajs in the remake); significant because they're one of the few enemies you can [[VideoGameStealing charm]] for Magic Tabs.
* ''VideoGame/MassEffect2'' has a technician. ''One'' technician. You fight him during Jack's recruitment mission, inside the room where the switch to release Jack from her cell is. He has the dubious honor of being by far the ''weakest'' enemy in the game--he has ridiculously low health, has only low shielding on higher difficulty levels, has no powers, and wields the weakest pistol in the game. Even on [[HarderThanHard Insanity]], you can pretty much defeat him by walking up to him and punching him in the face a couple of times (assuming your squadmates don't get him first).
** There's also the Bounty Hunter enemy on Thane's recruitment mission. Notably, he's the only krogan in the entire game who doesn't use a shotgun (he uses a [[HandCannon Carnifex]]) and is also the only one to use energy shields instead of biotic barriers or armor (though he does have armor as well).
** Several other enemies also count, even though they're just mission specific reskins of regular enemies, like Batarian Troopers, Sisterhood Initiates, and Freelancers.
* ''VideoGame/MassEffect3'' has three examples of this related to decisions earlier in the series. [[spoiler:In the second game, if you betrayed Samara for Morinth, then Morinth appears as a Banshee on the final mission. Also in the second game, if Legion was given to Cerberus instead of recruited as a party member, it is encountered as an enemy at the Cerberus Headquarters. In the third game, if the Grissom Academy mission was never completed, Jack will be indoctrinated and killed as a Phantom, also at Cerberus HQ]]. All of these enemies are identical to regular enemies gameplay wise, with the only difference being their name and, in [[spoiler: Legion's]] case, a different model.
* ''VideoGame/TheElderScrollsVSkyrim'' features a couple examples of enemies unique to their dungeon/quest. One is the Afflicted, the vomit-spewing worshippers of [[OurDemonsAreDifferent Peryite]]. (Afflicted ''may'' randomly appear in the wild, so to speak, but they're extremely rare and their obvious purpose is to guide you to said sidequest.) Another example, made stranger by the fact that there's no clear in-story explanation, is the Corrupted Shades in the quest The Break of Dawn. They were explicitly created by a necromancer, but he's far from the only necromancer in the game, and all others use either ghosts, zombies, or Draugr. The [[WatsonianVersusDoylist Doylist]] explanation might be that the quest is given to you by Meridia, a Daedric Prince who despises necromancy and the undead, and if the player fought more standard enemies (that didn't collapse into puddles upon death as the Shades do), they could themselves use necromancy within the quest.
* It happens in ''VideoGame/Folklore'', on account of how the player collects and upgrades attacks for their arsenal. Sometimes, the enemy required to upgrade the weapon will only spawn in a single room of the level, forcing a lot of grinding.
[[/folder]]

[[folder:ShootEmUp]]
* In the [[BrutalBonusLevel Special Stage]] of ''[[VideoGame/{{Parodius}} Gokujou Parodius]]'', just before the [[BonusBoss Robot Penguin]], you will encounter an enemy called the "16-Bit Block," which has 65536 hit points [[InvincibleMinorMinion and will scroll off the screen before you can do any significant damage]].
* There is one and only one Cellular Sheildeen in ''KidIcarusUprising''.
* In the ''VideoGame/AceCombat'' series, there are enemy aces. Often, they fly uniquely painted versions of the player's aircraft, and the unique paint schemes are awarded after successfully shooting them down. While they are more skillful than the standard mook, they aren't quite to the level of say, [[ThatOneBoss Yellow Squadron]]. They may also fly aircraft that aren't commonly encountered, such as the [[RussiansWithRustingRockets MiG 1.44]] or the [[JokeCharacter Hawk training jet]].
[[/folder]]

[[folder:Simulation]]
* ''[[Videogame/{{X}} X3: Terran Conflict]]'' has the Paranid Hyperion corvette and the Agamemnon frigate, which are [[SuperPrototype prototypes]] that never made it into production. Both of these [[LightningBruiser extremely potent]] ships only spawn once in the game, typically deep in Paranid sectors. The only way to acquire them is to [[BoardingParty board them with marines]]. ''[[GameMod Xtended Terran Conflict]]'' has the [[AIIsACrapShoot Xenon]] Raven, which is a modified Pirate frigate that uses [[PhotoprotoneutronTorpedo Xenon weapons]], and has the standard flaming NoseArt replaced with a slate gray fuselage outlined with glowing red TronLines. The Raven only spawns once, in the most heavily defended Xenon sector.
[[/folder]]

[[folder:StealthBasedGame]]
* There are a few unique enemies in the ''VideoGame/{{Thief}}'' series:
** There is only one Hammerite novice in the entire series, appearing in the ''Thief: The Dark Project'' level "Break from Cragscleft Prison".
** ''Thief II''
*** The level "Precious Cargo" features the only Mechanist frogman in the game. He has protective headgear, a portable light source, and a crossbow, making him extremely dangerous.
*** The standard Mechanist worker only appears in the ''Thief II'' level "Framed", but another one appears as a ghostly apparition later in the game, and there is also a character who is simply a HeadSwap of the worker.
*** The Spider Bot also appears only in the level "Sabotage at Soulforge".
*** Tree Beasts, appear (suddenly!) in only one section of the level "Trail of Blood", and in the ''Thief: Deadly Shadows'' level "Into the Pagan Sanctuary".
* ''VideoGame/MetalGearSolid'' had a fifth kind of Genome Soldier not listed in the manual and never mentioned in the game that wore dark-colored fatigues and breath masks. They only appear during two scripted events: the Comms Tower Chase and the Freight Elevator, and are never encountered patrolling an area.
[[/folder]]

[[folder:RealTimeStrategy]]
* ''{{Pikmin}}''
** In the original Pikmin, there was a powerful enemy called the Smoky Progg who would only appear during the first half of the game in the penultimate stage, in an egg. Notably, killing it gave you the highest Pikmin-producing item in the series, sprouting a full 100. It's shown alongside the other enemies during the end credits, confusing many players who missed it.
** There's also only one [[BlobMonster Goolix]] and [[HelpfulMook Mamuta]] in the standard mode, both of which are found ''in the exact same location'', but on different days. There is at least a Mamuta in the challenge mode, however the Goolix gets no such luck.
** ''Pikmin 2''
*** There is a single Toady Bloyster in the Perplexing Pool that holds a treasure. It's the only one you fight in the main game. You fight its bigger boss relative more times than this creature.
*** There are also orange bugs called [[http://www.pikminwiki.com/Secret_Wistful_Wild_bugs Ujadani]] that appear every 30 days in Wistful Wild starting with Day 31.
** ''Pikmin 3''
*** There's a bizarre creature called a Crushblat that you can encounter in a new area of the first level you can only access when get blue Pikmin. It has no fanfare, isn't tough enough to be considered a boss (or miniboss), and doesn't respawn after you kill it.
*** Despite being shown off in the trailers, there are only two Medusal Slurkers in the entire game, one you kill to rescue your first batch of rock Pikmin, and one hidden away in one of the trickier to reach secret areas, both of them are a joke, only able to kill Pikmin if you let them.
*** Several old enemies appear in challenge mode stages and nowhere else even in the main campaign.
* In ''VideoGame/AztecWars'', you begin the first campaign mission with two catapults. This unit never appears anywhere else in the game (neither in the campaign nor standalone missions) and cannot ever be built.
* ''VideoGame/StarcraftII'' one mission has player control the Odin, a massive mech that's an engine of destruction. This unit cannot be built, as it is a SuperPrototype of the Thor unit.
* In ''VideoGame/CommandAndConquerTiberianSun Firestorm'' the final mission has the player face a HumongousMecha the Core Defender which is huge and super hard to kill. The normal game has exactly one mission where the player fights against a base of the Forgotten, who utilize interesting military conversions of civilian hardware, such as camping trucks with missile launchers. They are fought exactly once again in ''Firestorm''.
* ''VideoGame/CommandAndConquerRedAlert'' and its sequels also often have unique enemies, sometimes unique enemy ''structures''. From Invicible Mammoth Tanks to Tesla Tanks made out of radar disruptors (later made into a unit in its own right) to Aztec structures with prism cannons and moai heads fitted with death rays or man cannons. The Allied campaign of ''Red Alert 3'' also has Noise Detector Ships used by the Empire which must be destroyed; they never crop up anywhere else.
* ''WarCraft'' III, several missions are filled with powerful creeps that can be considered as hero units, and boss fights.
[[/folder]]

[[folder:TurnBasedStrategy]]
* ''FireEmblem''
** Corsairs, which only appear in one chapter of ''The Blazing Blade'' and are effectively the same thing as Pirates, down to the same sprite. The only difference: If you hack a Corsair in your team, they can't [[PrestigeClass Promote]].
** In ''Blazing Blade'' most enemies are male, apart from representatives of classes that are AlwaysFemale like Troubadors. There are three exceptions to this in the entire game: a lone female Sniper in "Valorous Roland" and a pair of female Druids seen in the Hector Hard Mode and ''only'' the Hector Hard Mode version of "Cog of Destiny." The Sniper isn't anything special, but the Druids are real [[BossInMookClothing bosses in mook clothing]], as they're packing status-ailment inflicting staves and have suck a high Magic stat that their attack range for them is ''20 tiles''!
** To add another exception to that list, the nomads in The Dread Isle (HHM) have unique sprites as well.
* ''VideoGame/{{Odium}}'' has the Hornets (green insectoids) and Harvesters (scythe-handed maniacs) - mundane enemies in every respect, save that they only pop up in one combat. Granted, some other enemies pop up in only two or three, so it's not that unusual.
* ''VideoGame/ShiningForce'' has a pair of Dire Clowns found exclusively in the circus tent, the Laser Eye (which is more of a BossInMookClothing, seeing how you don't even need to destroy it), and an Evil Doll that knows Heal instead of Freeze found only in the Balbazak fight.
[[/folder]]

[[folder:SurvivalHorror]]
* ''VideoGame/{{FEAR}}''
** The Replica Assassins are only fought in the levels "Watchers" and "Point of Entry" (a total of 8 or 9 in the entire game), although lone individuals are briefly seen in "First Encounter" and "Exeunt Omnes".
** The Replica Snipers. They are identical (same health, same weapons...) to the regular Replica soldiers, except for their completely unique suit, and they only appear once: about 8 of them attack you on a roof during the level "Urban Decay", after that they don't appear anymore, not even in the expansion packs. The level also has a PoweredArmor unit armed with lasers instead of the rocket launchers used in all other encounters.
* ''Franchise/ResidentEvil''
** In some versions of the original ''VideoGame/ResidentEvil'' (specifically the ''Director's Cut'' and ''Deadly Silence''), the player gets to fight a zombie version of one of his character's S.T.A.R.S. teammate (specifically Forest Speyer). He also appears as an [[ActionBomb explosive-rigged]] zombie in the "One Dangerous Zombie" mode of the Gamecube remake, and killing or being grabbed by him causes instant death for the player character.
** There is only one giant moth in the entirety of ''VideoGame/ResidentEvil2'', in an optional out-of-the-way room in the lab basement. Screenshots of the beta (not ''RE 1.5'') showed more of them in other locations, such as the power room.
** In ''VideoGame/ResidentEvil3Nemesis'', you're only guaranteed to run into two of the Gamma-type Hunters (the froglike ones). There's a 50/50 chance of encountering two more on a walkway in the park.
** ''VideoGame/ResidentEvilCodeVeronica'' has the [[DemonicSpiders poison moths]] in [[ThatOneLevel that one corridor]], which you unfortunately have to traverse multiple times. When you revisit the area as Chris, they're gone, replaced by zombies. Earlier, in the passage to the seaplane port, several of the men comprising Wesker's private army can be found in zombie form. They're mostly notable for the light coming off their night vision goggles.
** Among the game's already rare Garradors (a total of four), ''VideoGame/ResidentEvil4'' has only one Heavy Armored Garrador.
*** The [[{{Animated Armor}} Armaduras]] (not to be confused with the armor suits that strike once, then collapse) only appear in a single room of the Castle.
*** Novistadors normally are either [[InvisibleMonsters invisible]] or [[AirborneMook airborne]], but not both; however, there is a lone invisible flying individual in the Nest Tower; after you kill it, it's gone forever.
*** The three [[UndergroundMonkey Iron Maiden]] [[DemonicSpiders Regeneradors]] in Chapter 5-2.
*** Also in Chapter 5-2 is [[ManOnFire Oven Man.]]
[[/folder]]

[[folder:TabletopGame]]
* Any GM of a TableTopRolePlayingGame should follow this trope. Regardless of genre, relying only on unmodified mooks without giving them a personality, motivation, and their own unique tricks is generally a very bad idea and a quick way to bore players. Additionally, generally an NPC should be unique, even if it's just one quirk to make them stand out. There are very, very few exceptions, such as an AllFleshMustBeEaten game where the GM wants to use just a single type of zombie and a world without other humans aside from the [[PlayerCharacter Player Characters]]. Even that is not recommended by the game system.
** TabletopGame/{{Pathfinder}} adventure paths always feature unique enemies almost every step of the way, along with the regular kind. So did too many TabletopGame/DungeonsAndDragons adventures to list.
** Warhammer and Warhammer 40,000 armies feature many unique characters which will fit this trope when your opponent fields them. Additionally, they can often build their own custom model and equip it as they see fit, meaning that enemy is truly unique since no one has built and painted their model just that way. This occurs in many miniatures games which have unique characters and heroes as usable units. Because these creatures are unique heroes of their faction, you can generally only field one of them. They can wind up in a MirrorMatch.
[[/folder]]
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