-> 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 HundredPercentCompletion 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 {{miniboss}}es 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. Contrast DegradedBoss, where an enemy ''seems'' like a unique boss, but returns later as a regular mook.

----
!!Examples:

[[foldercontrol]]

[[folder:Action Game]]
* ''{{Film/Batman}}'' on the NES has a cameo by the K.G. Beast, who will fight Batman prior at the end of the first stage to the actual boss battle with the Enforcer. He's a tough opponent, but the fact that he starts off relaxing against the wall means that canny players can, as noted by ''Magazine/NintendoPower'', rush up and punch his lights out before he can make a single attack.
* ''VideoGame/BionicCommando'' features unique enemies for some stages such as the [[HelicopterPack helipack]]-equipped Barrier Soldiers (replaced by Propeller Droids in the remake) in Area 5, the [[ThrowABarrelAtIt barrel throwers]] and [[DroneDeployer Remote Control Soldiers]] in Area 6, the Mobile Cannons and Helicopters in Area 7, the shield soldiers and 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. In the remake, most of these are more widely distributed.
* ''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.
* ''Franchise/{{Contra}}'':
** The arcade version has a pair of frogmen that jump out of the water and try to stab you with their knives at the beginning of the first stage when the game is played on Hard or Very Hard. They never appear again for the rest of the game and were cut from the NES version.
** ''Super C'' (the NES version of ''Super Contra'') has a single grenade throwing [[{{mooks}} 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 throwing enemies in the first stage.
* ''VideoGame/FinalFight'' - Round 3 features a steel cage match against two Andore variants (or three if you're playing co-op) that only appear in this specific area.
* ''VideoGame/JourneyToSilius'' - The third stage has the PersonalSpaceInvader [[FanNickname known as]] [=HumpBot=], which fortunately only appears about four times, and is not seen in any other stage.
* Franchise/MegaMan
** ''VideoGame/MegaMan2'' has only two Big Fish in the entire game, both in Wily 3.
** ''VideoGame/MegaMan5'' - The Rounders (flying eye robots) that show up at the end of the first stage in Proto Man's Fortress will simply circle around Mega Man until he either enter the boss gate or he shoot at them until they go away. They don't appear anywhere else in the game.
** ''VideoGame/MegaMan7'' - In Shade Man's stage, there are transforming knight robots called Gilliam Knights 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 forms).
** ''VideoGame/MegaManX1'' - In Armored Armadillo's stage 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.
* ''VideoGame/PunchOut'' (NES version) - King Hippo is the only boxer without a HeadSwap.
* ''VideoGame/{{Shinobi}}'' (UsefulNotes/{{P|layStation2}}S2 version) - Many enemies appear only in bossfights, and they're often small flying enemies themed with the boss to facilitate the game's SingleStrokeBattle mechanics, including fire-breathing heads for [[PyroManiac Homura]], giant snakes for [[AnIcePerson Kurokuda]], laser-spitting masks for [[HumongousMecha Yatsurao]], shikigami for [[spoiler: Ageha]] and sentient paper charms for [[BigBad Hiruko]].
* ''VideoGame/StreetsOfRage 2'' - The game has a number of regular {{mooks}} 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]]).
* ''Franchise/TeenageMutantNinjaTurtles''
** ''[[VideoGame/TeenageMutantNinjaTurtlesTheArcadeGame The Arcade Game]]'' - The NES version has two exclusive stages that each feature a unique roster of enemy characters. Scene 3-1, a snow level, features Hitmen Frosties (hopping mechs disguised as snowmen), snowball-throwing Foot Soldier, and an invincible snow plow. Scene 6, which is set in a Japanese dojo, has Blades (hunchback ninjas), Venomous Scorpions, and Vincent Van Growls (robot tigers that come to life out of door paintings).
** ''[[VideoGame/TeenageMutantNinjaTurtlesTheManhattanProject The Manhattan Project]]'' for the NES 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.
** ''[[VideoGame/TeenageMutantNinjaTurtlesTurtlesInTime Turtles in Time]]'' - The penultimate level, Starbase, has a robot moving up and down who fires lasers at you. It takes one hit to kill, and no more appear.
* ''VideoGame/LollipopChainsaw'' has the named zombies... while some are mini-bosses, most are just slightly stronger mooks. They give more experience and bonuses once killed.
* ''VideoGame/{{Battletoads}}'' on the NES has only one Yellow Swellcheeks, which flies erratically around the uppermost level of the Dark Queen's Tower, threatening to blow you off the platforms, and is [[InvincibleMinorMinion impossible to hit]].
[[/folder]]

[[folder:ActionAdventure]]
* ''Franchise/TheLegendOfZelda''
** In ''VideoGame/ZeldaIITheAdventureOfLink'':
*** Mago, a difficult to kill fire wizard, mercifully only appears in the fifth palace, though several times within it.
*** 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''
*** The blimp-like Octoballoon that splits into multiple smaller Octos appears near the southeastern 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}} Anti-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.
*** [[Franchise/{{Mario}} Boo Buddies]] only appear in one room in the Bottle Grotto dungeon, guarding the Power Bracelet.
** ''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''.
*** Tailpasaran are only found in one corridor in 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 [[TheGoomba almost no threat]], but unlike other [=ChuChus=] it doesn't contain an item, its true function is to be [[HarmlessFreezing frozen]] into a block for use as a [[CraniumRide platform]].]]
*** ''Majora's Mask'' has one Peahat in a hidden grotto 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 all over [[TheOverworld Hyrule Field]].
*** 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 its eyes while the other doesn't.
*** There are only two Desbrekos in ''Majora's Mask'': one in a tank in the Pirates' Fortress, and another in Great Bay Temple.
*** The American and European versions of ''Majora's Mask'' has a single place where Skullwalltulas can be found: a grotto in Termina Field. This isn't the case in the Japanese version, where another grotto with Skullwalltulas exists. It is in the path you need to take to reach the Bean Seller, [[RegionalBonus this path was simplified for the international releases]].
** ''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'' has the Pols Voice, which only show up twice in very specific places in the Temple of Courage.
** ''VideoGame/TheLegendOfZeldaTheWindWaker'' has a lone bomb-spitting River Octorok in one room in the second visit to the Forsaken Fortress, and the Orange Wizzrobe in the Wind Temple.
* ''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 ''VideoGame/TombRaider'' and ''VideoGame/TombRaiderIII'', Tigers in ''VideoGame/TombRaiderII'' 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.
** In ''VideoGame/TombRaiderTheAngelOfDarkness'', there is only a single PlantPerson in the Bio-research Facility who busts out of a tank, and a lone orange jumpsuit-wearing Prisoner in The Sanitarium who won't attack you. There are also only 2 Leviathans; one in the Bio-research Facility, and another in the Aquatic Research Area.
* Games based on ComicBook/{{Batman}}'':
** A justified example occurs in ''VideoGame/BatmanArkhamKnight''. A Militia leader is seen giving his soldiers a briefing about what he believes is a fool-proof method of defeating Batman: a suicide vest that will explode upon the incapacitation of the wearer, killing them and causing Batman to break his no killing rule. However, his men are understandably hesitant to embrace the idea (what if a soldier wearing the vest falls asleep?), and the leader has his vest disarmed without much fanfare. No other vests are encountered in the game.
** ''VideoGame/BatmanArkhamAsylum'' has after a certain point in the story a few Blackgate thugs wearing Arkham Asylum rain slickers in a feeble attempt to ambush Batman. Nowhere else in the game do they show up.
[[/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 the Subspace Emissary on a display room on the Halberd, but it has a trophy... that details just how there's only one of him in the whole game. Files from the game suggest he was originally going to appear, but he was ultimately DummiedOut.
[[/folder]]

[[folder:First-Person Shooter]]
* ''VideoGame/HalfLife'' series.
** In ''VideoGame/HalfLife2'', the Claw Scanners appear in a couple of chapters and don't appear again until late in Episode 2.
** In the original ''VideoGame/HalfLife1'', 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.
** Only one of the Black Ops' grunts uses the Sniper Rifle. All others use the [=MP5=].
** The alien auto-cannon. One appears in one corridor in the original game, having been set up by Alien Grunts, and nowhere else.
** 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 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 "343 Guilty Spark" you encounter a Marine driven insane by the (then-unencountered) Flood who will slowly shoot at the Chief when approached. His shots are too slow to do any real damage, and he can be left alone or killed with no consequence.
*** 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.
*** In "Outskirts", you encounter a convoy of Shadows. Despite receiving an entry in the game manual, it is undriveable, only found in this level, and overall acts more as a set piece than an enemy.
** ''VideoGame/Halo3ODST'' has an NMPD officer who will turn on the Rookie because HeKnowsTooMuch on "Data Hive"[[note]]But only if you've already collected 29 audio logs, then followed the cop after the part where he tells you not to[[/note]]. 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.
** ''VideoGame/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.
*** The Elite Field Marshal is the only one of its rank in "Pillar of Autumn". It is basically a high-ranking Zealot that rapidly fires a fuel rod cannon and throws grenades at the player. When it's shields are down and when the player is close, it unsheaths its Energy Sword in an attempt to One-Hit Kill the player.
*** 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.
* ''VideoGame/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 [[AttackDrone 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 [[Franchise/{{Halo}} Covenant Elite]], so they could have easily been used more often without being unbalanced, especially in the later levels. The only obvious reason why they weren't used more often was their terrible AI, especially compared to normal soldiers; most of their difficulty comes from facing them in groups and their buffed HP.
** 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.
* ''VideoGame/{{Wolfenstein 2009}}'':
** 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.
** There is also only one Panzerschrek-armed Mook in the entire game. He appears in the level "Farm".
* The "Bouncer" Big Daddy enemy that serves as the SeriesMascot of ''VideoGame/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''
** There is 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.
* ''VideoGame/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 ''VideoGame/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 ''VideoGame/{{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.
* The ''VideoGame/DarkForcesSaga'' games generally have at least one of these per game, although a lot of them function more as bosses in all but name than as mooks - the Rancor is a particular common one, a single one appearing in ''VideoGame/JediKnightDarkForcesII'' and two, one mutated, across ''VideoGame/JediKnightJedIAcademy''. ''Academy'' has two of possibly the most unique enemies in the series, both variations on the standard Mercenary - one in the Coruscant level is the only one to carry a heavy repeater rather than an E-11 (as part of a ShoutOut to the developer's earlier ''VideoGame/SoldierOfFortune'' series), and another in Nar Kreeta is 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.
* Guard dogs tend to fill this role in ''VideoGame/CallOfDuty'' games, thanks in part to their DemonicSpiders status when they're ''not'' limited to one or two levels.
** There is exactly one guard dog in ''Videogame/CallOfDutyBlackOps''. It appears in the beginning of "WMD".
** In the previous ''Call of Duty: World at War'', you encounter only about three guard dogs in the entire game, all of which you fight exclusively in "Vendetta".
** The same more or less applies to ''Call of Duty: VideoGame/ModernWarfare 3''. Guard dogs are exclusive to the level "Eye of the Storm" and its Spec Ops variation "Resistance Movement", while the similar hyenas only appear in "Back on the Grid" and its variation "Fatal Extraction".
** ''VideoGame/CallOfDutyBlackOps3''[='=]s "Demon Within" level marks the only campaign appearances of Nazis, Dire Wolves, and then [[VideoGame/NaziZombies zombies]].
* ''VideoGame/Wolfenstein3D'' has "floating vampire Hitlers" which hurl streams of fireballs at you in the final level of episode 3 and ''VideoGame/PacMan'' ghosts in the secret level of that episode.
* ''VideoGame/{{Doom}} II: Hell on Earth'', for its secret levels based on the above ''[=Wolf3D=]'', has that game's blue-clad SS enemies to populate them. They're a lot less dangerous here than in their home game, so the developers throw more of them at you to help make up for your superior firepower.
** The Playstation port of DOOM features a single translucent Cacodemon that's locked in a cage in the level Tenements. [[SubvertedTrope This is most likely an error, however]], since translucency is a flag that can be set to any monster, but is only used to create the Spectre enemies.
* ''VideoGame/WolfensteinTheNewOrder'' has several enemies who could be classified as unique. The 1946 variation of the Super Soldier is fought one time unarmed, and two are fought much later, armed with machine guns. Secondly, a single Heavy Robot is fought as a miniboss at the end of the London Nautica level. Finally, the Panzerhund is fought head on in the penultimate level after being encountered as an environmental hazard in many other levels.
[[/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.
*** The Dachora and Etecoons that taught you moves to get out of certain traps earlier in the game can be saved at the end by entering a side room and shooting the wall during the escape sequence. No reason [[VideogameCaringPotential other than to help those who helped you]]. They actually appear again in [[spoiler:the final escape sequence in ''VideoGame/MetroidFusion''. ''Where they steer your ship away from the final boss to avoid destruction and bring it back to you at the end, effectively saving you'']].
*** The hallway just before Ridley has two "ninja" Space Pirates. The only other place they appear is during the escape sequence.
*** There is a [[http://metroid.wikia.com/wiki/Geemer unique Geemer]] colored like Samus's Varia Suit which mimics her movements above a particular room in Crateria. If you leave the room, it will be gone when you reach its spot. It doesn't do anything or drop anything special, it can't hurt you, and there is no explanation for it.
** ''VideoGame/MetroidPrime'':
*** [[http://metroid.wikia.com/wiki/Ice_Shriekbat Ice Shriekbats]] only appear in one room in the entire game (the Ice Ruins West area of Phendrana Drifts) and are ''infamous'' for how easy it is to [[PermanentlyMissableContent lose]] their MonsterCompendium entry if you don't watch for them. They blend in with the rocks they roost on until you get close and can be easy to mistake for the [[ComMons very common]] ordinary [[GoddamnedBats Shriekbats]] you've probably already scanned. When you get close they dive bomb into you killing ''themselves'' in the process and [[PunctuatedForEmphasis They! Don't! Respawn! EVER!!]] Even if they don't kill themselves, miss them and they disappear as soon as you get the nearby suit upgrade never to appear again, making it impossible to fill your logbook [[HundredPercentCompletion completely]]. Thankfully, the PAL version fixes this so they do {{respawn|ingEnemies}} and no longer arbitrarily disappear from the game if you miss them.
*** There's also Ice Parasites that only appear in two rooms and disappear from the game, there are several other one-time scans in this series too, but luckily they're not quite as easy to miss as the Ice 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.
** ''MetroidPrime2Echoes'' 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.
** ''MetroidPrime3Corruption'' has a few examples including the fast and [[ThatOneSidequest incredibly hard to scan]] Gel Ray found in pools of Fuel Gel.
* ''Franchise/{{Castlevania}}''
** ''VideoGame/CastlevaniaAriaOfSorrow'' has a couple of ordinary enemies who appear in just one room to frustrate HundredPercentCompletion, such as the super-fast flying fish enemy that requires a [=TimeStopper=] from ''another'' Unique Enemy, 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. One enemy, called the O, appears in only one room in the entire game and swipes your sub weapon if it manages to touch you. Letting it succeed is the only way to unequip your sub weapon and thus use Juste's healing spell.
** 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.
* In ''VideoGame/DarkCastle'', the [[Disney/{{Fantasia}} Magic Broom]] only appears in the Wizard's lair at the end of the Fireball path. In ''Return to Dark Castle'', they are a regular occurence.
* The Hardbeetle in ''VideoGame/{{Aquaria}}'' is a small, practically invincible and unimportant creature that appears in exactly one place.
* ''VideoGame/OriAndTheBlindForest'' has a spiny platform-circling InvincibleMinorMinion that appears in one section of the Ginso Tree and nowhere else.
[[/folder]]

[[folder:MMORPG]]
* ''VideoGame/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.
** There exist a handful of tamable beasts that have unique appearances, and they're sought after both by players looking for loot or achievements and hunters looking to tame them. Notably, the Spirit Beast family of pets is almost entirely made up of unique pets with respawn timers that range from hours to days, and killing them rather than letting a hunter tame them is something of a universal FandomBerserkButton for the ''[=WoW=]'' hunter community.
* 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.
* Giants in ''VideoGame/GuildWars2''. Outside of four bosses (one of which is found in a dungeon), they're only encountered during a quest in Brisban Wildlands that spawns between one and six of them, depending on the amount of players present. This makes the Giant Slayer achievement, which requires killing a thousand of them, infamously difficult, and turns the aforementioned quest into a frantic rush to land a hit on at least ONE before the rest of the player mob wipes them out.
[[/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 {{Trope Namer|s}}.
** ''VideoGame/SuperMarioBros3'':
*** The Missile Bill (which has a homing ability) only appears in World 4-5.
*** The shoe-wearing Goombas appear only in World 5-3.
*** The game also has the Spiny Cheep-Cheep and a lone ''fire-breathing'' Nipper (both found in World 7, 7-4 and 7-8 respectively).
*** The Parabeetles are only found in one level of World 5: 5-6, on the sky portion of the map. 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 Angry Sun in an unnumbered stage of World 2 and World 8-2. The former also has a whirlwind-like obstacle that shows up nowhere else.
** ''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.
*** ''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/{{Super Mario Bros|1}}.'' 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.
*** The hopping flame enemies, called Bound Fire, are only found in the seventh Special World level, Outrageous. No, that doesn't mean that's their only appearance in the game, that's their only appearance in the entire ''Mario'' series.
*** Dry Bones appears in the majority of the castle and fortress stages, either staying on ledges or throwing bones (Valley Fortress has both types). However, the Dry Bones in Bowser's Castle both stay on ledges ''and'' throw bones, which is unique to that level (in fact, the enemy's code even checks for that specific level number). And the only Dry Bones in Bowser's Castle are two in the room for door 6.
*** [=SMW=] has a couple other type-sensitive Unique Enemies as well: Grinders, the rotating circular sawblades, show up in a few different castle and fortress stages, but the only place they are found without accompanying line guides is the second room of Forest Fortress. Similarly, the small fireballs spat by Bowser statues also appear without the statues, by themselves in the level and spawned from a generator, only in the first room of Chocolate Fortress. For that matter, the jumping and inactive (stationary, non-fire-breathing) variants of the statues are unique to door 7 in Bowser's castle (the fire-spitting ones show up there as well as Roy's castle), with three jumping statues and but a single inactive one.
** ''VideoGame/SuperMarioWorld2YoshiIsland'':
*** 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, and in an optional room at that. It does appear in one of the secret levels added to the GBA version.
*** The Flutter enemy is continually generated where it appears, but it is found only at the very end of 4-1.
*** [[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 ''Super Mario 64 DS'', the only Manta Ray, Sushi, 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 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 level: It's found in the ice-themed multiplayer stage of [[VideoGame/NewSuperMarioBros1 the first game]].
*** A puffy-lipped Bob-omb enemy called a Kab-omb, also from the first game, only appears in World 8-8 and doesn't show up anywhere else. Bizarrely, it makes a reappearance in a ''Videogame/MarioGolf'' game as an item.
*** Snow Spikes, a snow-themed variant of the Spike (those guys from ''[=SMB3=]'' and beyond who barf up spike balls and throw them) only appear in 5-1 of ''[=NSMB1=]''.
*** In the game ''VideoGame/NewSuperMarioBros2'', the only Sledge Bro appears in level 2-2.
*** And even in [[VideoGame/NewSuperMarioBros1 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.
*** The once-common [[VideoGame/SuperMarioBros3 Fire Chomp]] has become this in ''VideoGame/NewSuperMarioBrosU''. It shows up in one level in the final world, and is truly unique in the aspect there is really only ''one'' in the whole game.
** ''VideoGame/SuperMario3DWorld'' has a few:
*** The Charvaargh shows up only in the final section of 7-7.
*** The Fuzzler is exclusive to 3-7.
*** Cheep-Cheeps and Porcupuffers only appear in 3-5.
* In ''VideoGame/SpyroAHerosTail'', in the level Dragonfly Falls, there is an angry shepherd who will send goats to attack you. He and his goats disappear permanently when you defeat them (although one of the goats appears in the Model Viewer), and don't even respawn when you die. The same level also features rock-throwing monkeys that don't appear anywhere else in the game.
* ''VideoGame/{{Kirby}}''
** ''VideoGame/KirbysDreamLand3'' has two examples. The first is Polof, a rabbit-like creature that appears in one level of Sand Canyon, and quickly disappears into a background wall when you approach. [[FollowTheWhiteRabbit It serves a purpose though]]: [[spoiler:That spot where it vanished is a secret door leading to a room filled with items.]] The second is a creature called Batamon, it looks like Kirby and almost always appears marching behind walls and other unreachable areas. Although they appear quite a few times in the game there is usually no way to engage them directly, however, in one of the AutoScrollingLevels in Cloudy Park you can continue past the goal and find a secret room full of them.
** ''[[VideoGame/Kirby64TheCrystalShards Kirby 64]]'' has waddling black enemies called N-Z. Meant to serve as a replacement [[TheGoomba Goomba]] for the Waddle Dee in the rest of the series (since a Waddle Dee is an [[BreakoutMookCharacter ally]] in this game)...but then they don't appear anywhere in the game outside of the first level, and the very last section of the last level where they drop out of a black cloud implied to be [[EldritchAbomination Dark Matter]].
** ''Kirby and the Amazing Mirror'' has a single Squishy tucked away in a water-filled area of Moonlight Mansion. Squishy were fairly common in the previous game (''Kirby: Nightmare in Dream Land'') but here there is only one and it's found in the flooded basement of a ''haunted'' mansion not the game's actual [[UnderTheSea ocean level]] more befitting of a squid-like enemy.
* ''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.
* ''VideoGame/DonkeyKongCountry'':
** ''VideoGame/DonkeyKongCountry1'' has the Rockkrocs in "Stop & Go Station", and the almost completely invincible gray Krushas in "Platform Perils".
** ''VideoGame/DonkeyKongCountry2DiddysKongQuest'' has:
*** 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.
** ''Many'' examples in ''VideoGame/DonkeyKongCountry3DixieKongsDoubleTrouble'', 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 later levels, Swoopy Salvo. However, you can find just one other Swoopy in one of the earlier 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, Kroc from Krack Shot Kroc does this, except from the fourth-wall side of the screen. Although you play as Kroc 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 known as Koindozers 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 acorns 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, named Kracka which acts similarly to the Knocka enemy.
** ''VideoGame/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 Gnawties are TheGoomba for this game, but they are only found in DK Isles, Jungle Japes and Crystal Caves.
* Klobber, a common enemy in ''Donkey Kong Country 2'', appears in only one part of one level in ''VideoGame/DKJungleClimber''.
* ''VideoGame/PrinceOfPersia1'':
** The Politician, a GiantMook fought at the end of Level 6. This isn't technically a boss, as he is only slightly tougher than the regular {{Mooks}}. 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 UsefulNotes/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.
* 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 [[Franchise/StreetFighter Ryu]], [[VideoGame/MarioPaint a plane]], and [[VideoGame/SuperMarioBros2 the Red Snifit himself]], armed with a BFG.
* The 8-bit version of ''VideoGame/{{Sonic the Hedgehog|1}}'' 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.
* ''VideoGame/BanjoKazooie'':
** There is a black-colored Snippet in the sand castle of Treasure Trove Cove. It's twice as enduring as the other Snippets in the game, including the Mutie variety that is fought in Clanker's Cavern as a WolfpackBoss.
** In ''Tooie'', [[AmusementParkOfDoom Witchyworld]] is filled with Jippo Jims (the rat enemies armed with mallets), but that only goes for the costumed ones found in the attraction areas. The beginning of the level has a lone non-costumed Jim.
* The rare arcade platformer ''J. J. Squawkers'' features at about the beginning of the first level a white monkey with a human face (!) and Mickey Mouse ears (!!) shaking a tree to let dangerous fruits fall down. It lets out a hilarious death scream when defeated. Level 3 has a tough yellow walker mech that shoots tons of missiles and can be considered a BossInMookClothing.
* Every game of the original ''Franchise/CrashBandicoot'' trilogy has at least one weirdly underused enemy that you often have to go out of your way to find.
** The [[VideoGame/CrashBandicoot1996 first game]] has 2 or 3 gun-wielding gangsters that are only found in "Cortex Power". They show up in side paths that lead nowhere, meaning you're not required to confront them unless you're aiming for all crates.
** The [[VideoGame/CrashBandicoot2CortexStrikesBack second game]] has Cyborg Armadillos and Hunter Lab Assistants, found only in secret areas of "Unbearable" and "Bee-Having".
** The [[VideoGame/CrashBandicoot3Warped third game]] has Arabian Sword-Throwing Assistants, which only show up in "Flaming Passion". You only find one regularly, while 3 more are found in a difficult-to-get secret path.
** Outside of the trilogy, ''VideoGame/CrashTwinsanity'' had a lone barrel-throwing Rhino pirate in "High Seas Hi-Jinks" and only two groups of Driller Ants, one at the end of "Rockslide Rumble" and another partway through "Ant Agony".
* In ''VideoGame/Rayman2'':
** Mini Janos only appear in "The Cave of Bad Dreams" and in "The Sanctuary of Stone and Fire", as a group in the former and a lone individual (Or two in the PS1 version), and are even more unique in that they behave differently in the two levels. The ones in "The Cave of Bad Dreams" dig into the ground, pop up somewhere else, then move forward for a while before digging again, breathing fire at you or grabbing you and eating you when you get too close, while the one(s) in The Sanctuary of Stone and Fire either hides behind a pillar and keeps it between you and him until you turn your back at him, at which point he will zoom out towards and try to jump on you, or in the PS1 version they patrol a set pattern around the room, breathing fire at you when you get too close or attack them.
** The N64, PC, Dreamcast, DS, 3DS and PS2 versions have only two Ninja Henchmen, one at the end of "The Precipice", and another one either in the interior of "The Prison Ship" in the N64, PC, Dreamcast, DS and 3DS versions or "The Echoing Caves" in the PS2 version. They are more common in the PS1 version, though, where one acts as the boss of "The Sanctuary of Stone and Fire", and [[DegradedBoss more appear a bit later as regular enemies]] in The Precipice, "The Tomb of The Ancients" and "The Gloomy Island"
[[/folder]]

[[folder:Puzzle Game]]
* In ''[[VideoGame/DeadlyRoomsOfDeath DROD: King Dugan's Dungeon]]'', spiders appear only in Level 10. In the sequel, ''Journey to Rooted Hold'', they appear only in two rooms.
[[/folder]]

[[folder:RailShooter]]
* ''VideoGame/TargetTerror'''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 ''VideoGame/TimeCrisis2'', 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 ''VideoGame/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 ''VideoGame/NetHack'', shades and skeletons are moderately-powerful undead who only appear on the level dubbed "Orcus Town". Compared to the game that inspired it, ''Dungeons & Dragons'', shades are also fairly uncommon enemies, but skeletons are low-level monster fodder you would expect to see alongside zombies on the second and third floors of the dungeon, not halfway through your literal trip down into hell.
* ''VideoGame/TheBindingOfIsaac'' has Brimstone Grimaces, variations of the common InvincibleMinorMinion that fires out straight-line blood lasers. Not only do they ''only'' appear in [[spoiler:Sheol]] (and not even in the extra BrutalBonusLevel after it), but in very few room layouts. It's possible to go through several [[spoiler:Sheol and Dark Room]] runs in a row without ever even seeing them.
[[/folder]]

[[folder:Role-Playing Game]]
* ''VideoGame/{{Mother 3}}''
** The game has Negative Man, a rather unremarkable and comically-underpowered [[JokeCharacter Joke Enemy]] that 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.
* ''VideoGame/{{Fallout}}'':
** ''VideoGame/{{Fallout 3}}'':
*** At the bottom Vault 106, you encounter an apparently sane 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.
** ''VideoGame/FalloutNewVegas'':
*** There's a Mr. Gutsy Prototype in one of the houses in Nipton. Searching around reveals it was part of a man's bizarre attempt to impress women, serving a small bit of comic relief in an otherwise bleak area.
*** The Crashed Vertibird is the only location to feature the Hardened varieties of Mr. Gutsy's and Sentry Bots.
*** 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 [[SillinessSwitch 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'' only appear during the sidequest "The Treacherous Road".
** ''VideoGame/{{Fallout 4}}''
** The Wreck of the FMS Northern Star is home to a unique gang of [[NinjaPirateZombieRobot Norwegian-speaking Ghoul Raiders]], which nonetheless are statistically no different than normal Raiders.
*** Berserk Raiders are only encountered in the Parsons State Insane Asylum, during the quest "The Secret of Cabot House".
* [[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).
** ''VideoGame/PaperMario''
*** Bullet Bills can only be fought once at the very end of the Koopa Bros. Fortress. Once you beat the Bill Blasters that shoot them, they're pretty much impossible to fight again besides a golden variation found at Bowser's Castle.
*** The weird flying jellyfish-like creatures ([[AllThereInTheManual named only in the manual as "Sentinels"]]) that patrol Tubba Blubba's Castle in ''VideoGame/PaperMario64''. They can't be fought, and only act as {{Mook Bouncer}}s.
*** The Amazy Dayzee is found only in one spot in the Flower Fields and is randomly generated to be there about 10% of the time. The rest of the time, it's a normal Crayzee Dayzee. [[BossInMooksClothing It is also ridiculously strong]] and likes to run away as soon as possible, but if Mario can defeat it before it runs or he dies, the Amazy Dayzee will provide a mountain of experience points.
*** Boss-summoned enemies are pretty much exclusive to their fights, like the Tutankoopa's Chain Chomp, Lava Piranha's Petit Piranhas, the Crystal King's Crystal Bits and General Guy's Stilt Guys and Shy Stacks.
** ''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 Ultibed 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 Unique Enemy 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). It is also the only mon capable of using Light of Ruin.
* ''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 exactly 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...
* ''VideoGame/XenobladeChroniclesX'' has the Tyrants. Just like the original, they tend to be buffed enemies or have a special talent that makes them dangerous. And they have their own theme, "Uncontrollable".
* ''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]] [[Anime/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/MassEffect1'':
** The game has the Geth Repair Drones. They do not attack, and are only capable of repairing their Geth allies. They only appear once on Noveria, and are never seen again.
** The Rachni Brood Warriors only appear in one non-essential sidequest.
* ''VideoGame/MassEffect2'':
** The game 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 are also only two specific Krogan enemies who don't use shotguns (they use [[HandCannon Carnifex]] pistols) and have energy shields instead of biotic barriers. One, the Bounty Hunter, is encountered during Thane's recruitment mission, and the other, Kalusk, is found in a sidequest. The Bounty Hunter is particularly notable, as he's the only krogan found working with Eclipse.
** The Geth Recon Drones return from the first game, but now they only appear in ''one'' level, Tali's recruitment mission.
** Several other enemies are technically mission specific reskins of regular enemies, like Batarian Troopers, Sisterhood Initiates, and Freelancers.
* ''VideoGame/MassEffect3'':
** The game 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.
** Geth Pyros are surprisingly rare in the third game's main story, especially since they approach GoddamnedBats level in multiplayer. Aside from a one-off cameo, they only appear in ''one'' mission during the third game, and a side mission at that. [[https://www.reddit.com/r/masseffect/comments/5ao6wl/the_normandy_teams_kill_count_counted_and/ There's a grand total]] of ''eight'' of them in the entire game (out of the literally ''thousands'' of enemies you kill) despite being no tougher than the other common EliteMooks you slaughter by the hundred.
* ''Franchise/TheElderScrolls''
** ''[[Videogame/TheElderScrollsIIIMorrowind Morrowind]]'':
*** There are several which are involved with side quests including Old Blue Fin (a unique, named Slaughterfish,) [[ExactlyWhatItSaysOnThetin a Giant Bull Netch]], The White Guar (and several named pack guars,) The Dreugh Warlord.
*** One particularly notable example is Beldoh the Undying, a unique named skeleton found in the very late-game dungeon Vemynal, within Red Mountain. He seems very out of place in a Sixth House citadel surrounded mostly by Ash creatures and Corprus beasts, and is in fact one of the weakest enemies in the area he is in. Still, he carries one of only two Blood Feat shields in the game. He's not related to any quest and there is no mention of him or his backstory anywhere else in the game.
*** The Worm Lord is a powerful skeleton that can be found in his tomb in the Urshilaku Burial Caverns. While one does need to visit the caverns as part of the main quest, the Worm Lord is in his own section which is completely optional to visit. He's a relatively tough foe and guards some decent loot, but he has no known backstory. He is also notable for being one of the few non-humanoid enemies in the game that cannot be soul trapped.
** ''[[VideoGame/TheElderScrollsVSkyrim Skyrim]]'' 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.
* ''VideoGame/JadeCocoon'' has Arpatron, Korus' minion that can only be faced once in the entire game on your first trip through the Beetle Forest (When Korus is standing near the gate). It's a normal minion no more powerful than any other enemy in the forest that serves as a TrainingBoss and becomes yours as a bonus when you complete his training. It also happens to be the only kind of minion in it's entire ''family'' in the game; most minions have several variants (different colors and physical builds but same basic appearance) while Arpatron is the ''only'' capturable minion of it's kind.
* ''VideoGame/{{Undertale}}'' has both enemies that you can only {{Random Encounter|s}} once (Lesser Dog, Shyren), and enemy types that you can run into repeatedly, but contain only one member and will vanish forever when you kill that one monster (Snowdrake). Most of the first type are actually disguised PreExistingEncounters, though.
* ''VideoGame/DarkSoulsI'' has the Parasitic Wall Hugger--a huge but immobile monster encountered in Blighttown. Although it looks like there could be more of them lurking around, you won't actually encounter another anywhere else in the game, and once you kill it, it doesn't even respawn.
* ''VideoGame/DarkSoulsII'' has the giant ant thing in the Gutter. A completely unique, non-respawning enemy, which is completely harmless. All it does is sit there and belch gas, which degrades your equipment but also cures poison. It won't even make any moves as you hack it to death.
* ''VideoGame/MegaManBattleNetwork3'' has the '???' enemy. You fight a trio of them in a scripted battle late in the game, and no other time. It doesn't even have a name, because when you fight them no one knows anything about them. It also has an UndergroundMonkey variant called the Alpha Bug, which only occurs in the last room of the VeryDefinitelyFinalDungeon.
[[/folder]]

[[folder:RealTimeStrategy]]
* ''VideoGame/{{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.
* ''VideoGame/WarcraftIII'', several missions are filled with powerful creeps that can be considered as hero units, and boss fights.
[[/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 ''VideoGame/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 [[UsefulNotes/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 ''VideoGame/ThiefTheDarkProject'' level "Break from Cragscleft Prison".
** Craybeasts, the more powerful versions of Craymen, appear only in the last level of the first game. And even in this level you are likely to encounter only one or two of them.
** ''VideoGame/ThiefIITheMetalAge''
*** 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.
*** There are only two Hammerites in the game, in comparison to the original, where they are pretty common.
*** 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 ''VideoGame/ThiefDeadlyShadows'' level "Into the Pagan Sanctuary".
** ''VideoGame/ThiefDeadlyShadows'' has exactly 4 Ratbeasts, all of which appear only in the Sunken Citadel, and exactly 3 Hammer Haunts, which all only appear in the catacombs of Fort Ironwood.
* ''Franchise/MetalGear'':
** ''VideoGame/MetalGearSolid'' has a fifth kind of Genome Soldier not listed in the manual and never mentioned in the game that wear dark-colored fatigues and [[GasMaskMooks breath masks]]. They only appear during two scripted events: the Comms Tower Chase and the Freight Elevator, and are never encountered patrolling an area.
** ''VideoGame/MetalGearSolid3SnakeEater'' has the Flame Troops, of which there are only 3 in the entire game, and they all only appear in Krasnogorje just before the fight with The Fury. And unlike many of the examples on this page, there was a minor historical/story justification for this. Sigint explains that, in addition to being a short range weapon with limited ammunition, the soldiers carrying them have giant targets painted on their backs and are usually put to death when captured. So why do you see them at all? The reason changes depending on how you've been playing the game. They've either come of their own volition, as revenge for killing so many soldiers through the game, or if you've been playing nonlethally, [[spoiler:Volgin sends them as revenge for killing The Pain, The Fear, and The End]].
** ''VideoGame/MetalGearSolid4GunsOfThePatriots'' has the Power Suits, of which only a small group are fought in the beginning of the Drebin escape section of Act 2 and seen in the intro to the act.
* ''VideoGame/DeusExHumanRevolution'' has the Spec-Ops Shifters, of which there are only two in the base game in Highland Park with 5 more in The Missing Link, a lone Spec-Ops Ogre with a Sneaker's helmet instead of a Soldier's balaclava in The Missing Link during the battle with Burke, and a single group of [[spoiler:Crazy Spec-Ops]], which [[spoiler:you don't even get to sneak past/fight if you saved Malik, as she'll kill them all for you]].
[[/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''
** Starting with the Director's Cut version of ''VideoGame/ResidentEvil1'', Forest springs back to life to attack the player. In REmake, a mode is added called One Dangerous Zombie where he is covered with grenades, making attacking him suicidal.
** The [[ThreateningShark Neptune]]. You only find three of them in the same room, two small ones and a big one.
** The [=REmake=] features one unique zombie on a return trip through the graveyard late in the game. It's similar to the overweight, balding zombies seen in the mansion, except this one has no hair at all and wears only a pair of white boxers. No other zombies anywhere else in the game share this character model.[[note]]The HD re-release's HarderThanHard difficulties throw in one or two more[[/note]]
** Only one Sweeper appears in the [=REmake=], in the Kenneth Room on the return to the Mansion. Unlike the ones in Code Veronica, however, it can not poison you.
** 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. There is also only one room where players encounter mutated cockroaches.
** In ''VideoGame/ResidentEvil3Nemesis'', you're only guaranteed to run into two of the Gamma-type Hunters (the frog-like ones). There's a 50/50 chance of encountering two more on a walkway in the park.
** ''VideoGame/ResidentEvilCodeVeronica'' has the [[GoddamnedBats 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. Some of the zombies do show what happens if the moth eggs are allowed to hatch and grow, as a parasite of some kind will launch itself out of them in a couple of places. 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 and tendency to explode when shot. Finally, Claire only has to deal with the baby albinoids for all of 5 seconds.
** ''VideoGame/ResidentEvil0'' has the Lurkers, of which you are only guaranteed to run into once.
** Among the game's already rare Garradors (a total of four), ''VideoGame/ResidentEvil4'' has only one Heavy Armored Garrador.
*** The [[AnimatedArmor Armaduras]] (not to be confused with the armor suits that strike once, then collapse) only appear in two rooms 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. Another unique variant is completely white with black eyes.
*** The three [[UndergroundMonkey Iron Maiden]] [[DemonicSpiders Regeneradors]] in Chapter 5-2.
*** Also in Chapter 5-2 is [[ManOnFire Oven Man.]]
* ''Franchise/SilentHill'':
** In the American version of ''VideoGame/SilentHill1'', Claw [=Fingers/=]Mumblers only appear in the Sewers leading to the Amusement Park, and a lone one appears as part of a optional cutscene. They act like stronger versions of the Grey Children, doing more damage and taking more hits to kill. They are much more common in the Japanese and European versions of the game, though, where they replace the Grey Children in the Alley, School and Amusement Park.
** Possesed/demonic Nurses appear in virtually every ''Silent Hill'' game, as well as both of the movies, as virtually every game has a hospital level. They are practically mascots. Possessed doctors are a thing, too. However, they appear only ''once'' in the series, on the first floor of the first game's DarkWorld hospital.
** In ''VideoGame/SilentHill2'', in the prison, there are invisible monsters plodding around in a few inaccessible cells. They constantly whisper something like "ritual", and optionally, can be killed by James to no good or ill effect.
[[/folder]]

[[folder:ThirdPersonShooter]]
* In ''{{Vanquish}}'' the "L" version of the [[ActionBomb Jellyfish]] only appears in Mission 1-6.
* ''VideoGame/SpecOpsTheLine'' has only 7 Bayonet Runners out of hundreds of mooks. There are a low number of heavies - seven foot soldiers with massive armor and a BFG. There is only one of them who is a [[spoiler: hallucination of your deceased squadmate]], and he's incredibly challenging to beat. Lose to him, and you [[spoiler: flash back a bit to find he's replaced by a normal heavy, suggesting he was a hallucination]]. One other unique, very difficult heavy seemingly teleports about a room and flashes in and out of existence in a room full of mannequins. This guy has a very good chance of causing a Game Over, and his strange power seems to be a result of [[spoiler: the protagonist's frayed sanity causing him to hallucinate]].
[[/folder]]

[[folder:TurnBasedStrategy]]
* ''VideoGame/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 only a handful of exceptions to this in the entire game: a lone female Sniper in "Valorous Roland", several female Nomads in "The Dread Isle", and a pair of female Druids seen in the Hector Hard Mode version of "Cog of Destiny." The Sniper and Nomads aren't anything special, but the Druids are real [[BossInMookClothing bosses in mook clothing]], as they're packing status-ailment inflicting staves and have such a high Magic stat that their attack range for them is ''20 tiles''!
* ''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.
* One mission in ''VideoGame/FrontMission'' has Royd's unit attacked by enemy Wanzers that burst from beneath the sand and are operated by unique almost mechanical-looking pilots. Other than their [[DemonicSpiders aggravatingly good sand movement]] there's nothing statistically remarkable about them and they aren't unique machines like the [[SpiderTank Clinton-Type]] or [[BigBad Driscoll's Type-11DS]], but they never again appear in the game nor can you ever acquire any of their parts. Hacking reveals their parts ''do'' have rear-view sprites suggesting they were once intended to be obtained by the player but DummiedOut.
[[/folder]]

[[folder:WideOpenSandbox]]
* ''VideoGame/GrandTheftAuto'':
** ''VideoGame/GrandTheftAutoIII'' has the suicide bombers high on SPANK that are only encountered in a single mission, "Kingdom Come". Aside from their self-explanatory behaviour, they also continuously respawn from vans until those are destroyed.
** ''VideoGame/GrandTheftAutoViceCity'' has you fight a Costa Rican gang in "The Fastest Boat", and an all-woman counterfeiting syndicate in "Hit The Courier". Both of these gangs use standard pedestrian models, yet these are the only times they display gang behaviour.
** ''VideoGame/GrandTheftAutoIVTheBalladOfGayTony'' features one enemy APC in the game, during the mission "Frosting On The Cake". Notably, this APC is slightly different from the one you obtain as it has a machine gun turret instead of an auto-cannon.
[[/folder]]
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