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Single Specimen Species

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"But the most wonderful thing about tiggers is... I'm the only one!"
Tigger, The Many Adventures of Winnie the Pooh, "The Wonderful Thing About Tiggers"

Something that applies to many a videogame boss (especially in the case of a Giant Space Flea from Nowhere), kaiju or Monster of the Week — you come across a creature that looks unlike anything else you've seen or will see in that work's universe, but only once.

Creators contemplating for the existence of more of these tends to be a gap in their Worldbuilding, but tends to be a case where the MST3K Mantra applies in full force. It would be hard for an ecosystem to support more than one of it, after all, so just enjoy the game. And there are ways of justifying the existence of one single creature in works that bypass natural laws, at least as we know them.

For Long-Runners, this may become a temporary trope, as a family/species and natural habitat may be created for the being in question at a later time.

Obviously different from the One-Gender Race as there's only one specimen, and the concept of gender may not even apply. Also different from Last of His Kind, as that implies the existence of more of the same species in the past, or A Kind of One, where a whole species is known by the name of its most famous member, who may initially have been this.

Note that a Single Specimen Species is defined as being basically unexplained and therefore ecologically implausible. So the Last of His Kind can't "become" this, since that includes human survivors of a lost tribe, animals that were wiped out and so forth. However, A Kind of One may become an example in subsequent works, following the original; in which case it may be a case of Call a Smeerp a "Rabbit" since the characters have certainly never seen it before, but the readers have.

Not to be confused with Only You Can Repopulate My Race (which is ecologically implausible for entirely different reasons). Unique Enemy is the video game version — an enemy which pops up only once, though not necessarily because they're the only one in the world.


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    Anime and Manga 
  • Dragon Ball:
    • The Buyon, which could resist a Kamehameha in a relatively early stage of the series, was present only in a "boss tower" surrounded by an ecosystem in which it couldn't survive (Fridge Logic can be an important part of this trope — in this case, how did they bring the creature into the tower, and where from?). No other specimen ever appears again for the whole series, but it's interesting to see what would have happened if invaders had come across others of the same species — if others existed at all. Averted in Dragon Ball Online, where several of the same species (revealed to be aliens) appear as bosses.
    • Majin Buu has been around for a long, long time, but nobody, even those who were around when he first went on a rampage, seems to know where he came from, and if there are others like him they've never been seen. While Shin states that he was created by the wizard Bibidi, Akira Toriyama said that Buu has existed since time immemorial and Bibidi only figured out how to awaken him. Averted as of Dragon Ball Online, as there's a whole race of Majins that spawned from Buu.
  • The Four Knights of the Apocalypse setting has only one naturally born nephilim (goddess/demon hybrid), that being Tristan. His mother being both a goddess and a human, something almost as unlikely, probably had something to do with this.
  • Both used and subverted in Toriko. Many animals are so bizarre you don't expect to see another specimen, but sometimes one will show up.
  • Unlike the games, Pokémon: The Series doesn't regard most legendary Pokémon as this trope:
    • The Poké-Gods (i.e. Dialga, Palkia, Giratina, and Arceus) are known to be one-of-a-kind, while Lugia is shown to have a breeding population, and many of the legendary birds (Articuno, Zapdos, and Moltres) and legendary beasts (Raikou, Entei, and Suicune) are shown to have different members of the species encountered by the main heroes during the course of the series. Likewise, there has been shown to be more than one Deoxys in the series, and the Mew in Pokémon: The First Movie is a different Mew from the one in Pokémon: Lucario and the Mystery of Mew. Pokémon 2000 seems to imply that a specific set of the legendary birds (perhaps the progenitors of their respective species, but this isn't spelled out) are uniquely important despite looking the same as the others, since capturing them was catastrophic to the entire planet's weather. Pokémon: Zoroark: Master of Illusions features another set of Legendary Beasts that are different from the norm due to being shiny.
    • Mewtwo was created by humans and was the only member of its species as its creators were killed and all the research describing its creation was destroyed. That is, until Genesect and the Legend Awakened introduced a second Mewtwo that has no relation to the first (don't ask how that's possible, by the way). In the same movie, five Genesect are introduced as opposed to the lone one in the games.
    • Also, Latios and Latias are shown to be the offspring of another pair of Latios/Latias in Pokémon Heroes, and Shaymin in Pokémon: Giratina and the Sky Warrior is actually part of a group of Shaymin. There also appear to be two different Jirachi in Pokémon: Jirachi: Wish Maker and the Best Wishes episode "Wish on Jirachi: The Seven Day Miracle" (although the existence of two Millennium Comets is harder to explain).
    • Pokémon: Hoopa and the Clash of Ages manages to complicate matters by having its star Pokémon, Hoopa, capable of summoning a great number of legendary Pokémon from other dimensions. Almost all have appeared in previous movies, but it isn't known if the ones that appear in this movie are the same individuals (apart from Rayquaza, which is a shiny variant in Clash of Ages, making it a different member of a Single Specimen Species).
    • On the other hand, this appears to be played straight for one specific normal Pokémon. It's implied that Ash's Lycanroc is the first - and so far only - Dusk Form Lycanroc.
    • The Galarian fossil Pokémon in the anime are single specimen species due to being "frankenstined" from four unrelated organisms. Goh received an Arctozolt (a combination of a plesiosaur back half and a velociraptor front) and Ash received a Dracovish (a dunkleostus head on the tail of an unknown dinosaur).
  • Pokémon Adventures, in contrast to the anime, keeps the tradition of only one specimen with all Legendary/Mythical Pokémon. The only exceptions so far are Deoxys (where the only two specimens were twinned from the same space virus) and the Cosmog line (who are already known to avert this trope in the games' continuity).

    Comic Books 
  • Green Lantern: Adam is the only member of his species. He dies whenever he gives birth but his Power Ring lets him keep memories from previous generations.
  • The Sandman (1989): When the protagonist Dream, Morpheus, dies, there is a replacement Dream from a child named Daniel. Although Morpheus is definitely dead, Dream isn't. While the new Dream came from Daniel, he is not Daniel. And while the new and old Dream are treated differently by the rest of the cast, they aren't quite considered separate beings. As Abel put it, it's the same concept but a different perspective.
  • Star Wars Adventures: Only one Argora can be alive at a time, putting it at high risk of extinction.
  • Wonder Woman: While in some iterations of the comic's winged horses are a relatively common mount for Amazons, in Volume 2 Pegasus retains his unique status from mythology and is reborn after centuries when Medusa gets her head chopped off again.

    Fan Works 
  • Unusually for a Pokémon fanfic, Intelligence Factor averts this with most legendaries — it's explicitly stated that there are multiple Latis, Darkrais, Cresselias, and Tapus. It's played straight with Regigigas, though; only one has ever existed, because it was created by Zygarde for the sole purpose of shaping the world. Diancie is also a one-of-a-kind mutation.

    Film — Live-Action 
  • Godzilla and other more traditional kaiju sometimes are shown to have offspring, so they're right out. However, the viewers see no indication of a Gojiru population from which it might have sprang. The known Godzilla population is Godzilla (1954), Godzilla (Showa), Minya, Godzilla (Heisei), Godzilla Junior, Godzilla Millennium, Godzilla SOS, and Final Wars Godzilla. However, thanks to Canon Discontinuity, it's hard to tell if there are any others or of what relation they all are to one another in the first place. In Godzilla (2014), he is the last survivor of a race of alpha predators. Shin Godzilla is the first of a species actually created by radiation and marine microorganisms, not simply awoken or empowered by it, though potentially not the last.
  • King Kong:
    • In the original, to their knowledge they never see anything that could possibly breed with it on that island.
    • Both the original King Kong and its 1976 remake had sequels where a second giant gorilla shows up;
      • The Son of Kong has Carl Denham go back to Skull Island to find a second giant ape, who is thought to be the son of the original.
      • King Kong Lives has an explorer go to Borneo (which used to be connected to Skull Island) to find a second Kong to give the original a blood transfusion. He finds a single female which he brings back to America. By the end of the movie, Kong is dead again, but his mate and son live on.
    • Peter Jackson's 2005 remake and Kong: Skull Island kick this trope out the door, since it shows a lot of bones from Kong's species - he's made out to be the Last of His Kind.
  • Star Wars: The Sarlacc and the Exogorth (Space Worm), prior to the somewhat dubious explanation for each in the Extended Universe novels and books.
  • Subverted in Rodan. The eponymous mutated Pteranodons are shown to be a breeding pair.
  • The Heisei Gamera films:
    • Averted with the Gyaos. They can reproduce asexually and are soon able to attack in large swarms.
    • Likewise, subverted with Gamera himself. At first glance, it seems that he's the only one of his species. Then, during Awakening of Irys, we see that there were thousands of Gamera that existed before him, but were all killed out leaving him to be the last of his kind.
  • Gonzo from The Muppets was this for awhile before being revealed as an alien, since he himself didn't even know what he was. Invariable he was referred to as something like "a whatever he is".
  • The title creature of The Water Horse: Legend of the Deep is explicitly stated to be a Single Specimen Species. "The rarest of all creatures", there can only be one at a time. The creature is not depicted as magical, nor does the issue go unexplored: it's explained that each water horse lays a single egg and dies before the egg hatches, making the protagonists determined to protect the one they have in their possession.
  • Audrey Jr. from The Little Shop of Horrors is the only one of his kind in existence as he was a crossbreed between a butterwort and a Venus flytrap. In the musical, he's an alien so there are probably more of them in space but the only other one we see is in Seymour's flower bed after the original Audrey II is killed.
    • The play and the musical's Director Cut have them breeding and taking over America.
  • Ego from Guardians of the Galaxy Vol. 2 formed alone in space and had to search the universe for other lifeforms. He refers to himself as a Celestial, it's not clear if he's related to the "celestial beings" from the first movie which were based on the Celestials from the comics. This is possibly implying that Ego is a Boltzmann brain.
  • The Indominus Rex from Jurassic World, counts but also falls under being the Last of Her Kind when it's revealed that Ingen initially created two, but the bigger one ate its smaller sibling.
    • Played straight with the Indoraptor from the sequel Jurassic World: Fallen Kingdom, as only one was ever created, being a problematic and aggressive prototype for their planned weaponized dinosaurs.
    • This applies to the Mosasaurus. There isn’t any indication that Ingen or Masrani ever cloned another, leaving her as the only one of her kind on earth after surviving the abandonment of the park and managing to escape her lagoon into the open ocean.
      • To a lesser extent, several other dinosaurs have become, or are implied to be, the Last of His Kind as of this film—particularly, Blue is directly stated to be the last living Velociraptor after the rest of the Raptor Squad was killed in the previous film and Rexy, the original Tyrannosaurus rex is the only known surviving member of her species. However, the fourth and fifth seasons of Jurassic World: Camp Cretaceous and Jurassic World Dominion reveal that there are other raptors and Tyrannosaurs, meaning Blue and Rexy are not yet the last of their kinds.
    • This is also the case with the Spinosaurus from Jurassic Park 3, which is confirmed through viral marketing to have been something of a prototype Indominus as another hybrid, albeit one that actually resembles a fossil species.
  • Before Yaddle was created for The Phantom Menace, Lucasfilm didn't want Star Wars Expanded Universe writers mentioning Yoda's species. They wanted it left vague if he was unique or there were a whole race of them.

  • Cthulhu Mythos: most of the Great Old Ones. They can reproduce with each other (e.g. Lovecraft outlined Cthulhu's family tree), but for some reason the resulting offspring usually resembles neither parent.
  • The Lord of the Rings:
    • The Watcher In the Water, a strange mass of tentacles that hangs out in a relatively small and shallow lake waiting for passersby toting Artifacts of Doom to prey on.
    • Tom Bombadil; even the author isn't quite sure what he is, but he seems to be completely unique. His wife Goldberry also seems to be a completely unique being.
  • In the Mithgar books, which started as Tolkien fanfic complete with pseudo-Moria and pseudo-Watcher, there is eventually an explanation both for the ecology and how such a huge monster got into the isolated lake - it's a kraken, they're part of a Bizarre Sexual Dimorphism with dragons, and a dragon flew by and dropped it into the lake to annoy the dwarves. The dwarves manage to kill it by breaking the dam and draining the lake.
  • The title "character" in The Illuminatus Trilogy: Leviathan is a gigantic single-celled organism at the bottom of the ocean, a result of the first cell division that just got bigger and bigger while the rest of life on Earth developed into multicellular organisms. It's actually just a metaphor for the State. Straight out of Thomas Hobbes' article of the same name.
  • Discworld
    • In The Last Continent, the Wizards of Unseen University visit an island populated only with single specimen species. This is because the island is home to the god of evolution, who personally engineers each animal (and tweaks it as it goes along), and is blissfully unaware of things like sexual reproduction.
    • Carpe Jugulum deconstructs this trope vis a vis The Phoenix, arguing that one of anything, even if it can renew itself, won't last forever.
  • Adam in The Bible qualified, before Eve entered the picture. God Himself too.
  • Tigger from Winnie the Pooh. He gleefully rejoices in it too.
  • The Goo in Fluke, or, I Know Why the Winged Whale Sings is an enormous, unique, single-celled organism much like that from Illuminatus above, although it's not a metaphor, it's a great huge organism on the bottom of the sea. It's also the god that whales pray to which ensures there's always plankton. And it does.
  • The main characters in The Long Earth met First Person Singular that was travelling from its homeworld which was a Joker Earth (It Makes Sense in Context) where life evolved in an utterly different direction, staying at germ size but cooperatively working together to create intelligence. It covered the entire ocean, with land that's lifeless. However, when it stepped side-wise to the next Earth, only a portion of it went, so it's not a perfect example after stepping discovery.
    • In the sequels, this is retconned so there are millions of Earth's which evolved in a similar manner, and many examples of similar organisms wandering around the Long Earth. This is despite First Person Singular having been explicitly stated to be unique, and having been viewed as a major threat to the whole Long Earth by the trolls who have been living in and travelling it for millions of years. It goes from the main threat and climax of the first book to being handwaved as nothing special and then never mentioned again.
  • Sun Wukong himself from Journey to the West is the one and only specimen of Stone Monkey. According to Buddha, there are other three unique monkeys with singular powers; one of them, the Six-Eared Macaque, uses his powers to take Sun Wukong's form and tries to Kill and Replace the real pilgrims.
  • The last Twilight book, Breaking Dawn, has Renesmee - a human/vampire hybrid - as a Subverted example.
  • When arguing with Geralt about the existence of golden dragons in The Witcher: Sword of Destiny, Borch Three Jackdaws suggests their legends could have been based on a one-off mutant. He later turns out to be one so he could know what he's talking about.

    Live-Action TV 
  • Doctor Who:
    • In "The Battle of Ranskoor Av Kolos", the Doctor mentions that there have only ever been two Ux at any one time. Since the Ux are near-immortal Reality Warpers, that may explain how they reproduce.
    • "The Timeless Children" drops the revelation that the Doctor themself is technically one of these instead of an ordinary Time Lord, the only known example in this universe or dimension and possibly originating from another one. In fact, the Time Lords' ability to regenerate was taken from the Doctor, who has had countless regenerations prior to the first one the current Thirteenth Doctor is aware of — all the previous ones had been wiped from her memory. (Although they're not the only person in the universe exactly like them anymore, however: remember Jenny?)
  • Forever: Henry and Adam each believed themselves to be the only immortal in the world, until they learned of each other's existence.
  • One episode of How I Met Your Mother had Marshall and Lily discover a small animal living in their apartment that had the characteristics of both a cockroach and a mouse: they dubbed it a cockamouse. No such creature is ever heard of again after they threw it out the apartment window (don't worry; it can fly). The cockamouse turns up in a later episode, in a room in a rundown hotel that Ted stays in for plot-related reasons. He cheerfully reports that it's had babies.
  • In The Originals universe, there is only one tribrid, Hope Mikaelson.
  • Probe's "Computer Logic": Steve is a species of spider that exists only because Austin decided to mutate his great-grandmother with gamma rays and released her to the basement to observe the effects.
  • Subverted in Stargate SG-1. It looks to be a straight example when the Unas is first shown (his name certainly gives the impression). Another doesn't come along until two seasons later, at which point their nature as a species is explained (and Jack lampshades the confusing name.
  • A number of entities and creatures in the various Star Trek series.
    • In The Original Series:
      • The Guardian of Forever from "The City on the Edge of Forever". While the ruins around it seem to imply that it was artificially created, it claims to have always been. (Or at least to be older than Earth's sun.)note 
      • Redjak from "Wolf in the Fold", an entity who feeds on fear and death, and claims to be as old as time.
    • In The Next Generation:
      • The "Crystalline Entity" from "Datalore" and "Silicon Avatar" is a space-faring creature that consumes organic matter from entire planets. No other examples of its species are seen (until the MMORPG came out, at least).
      • Ronin from "Sub Rosa" is a ghost-like lifeform apparently from Earth that bonds symbiotically with a human female, giving her pleasure in exchange for some kind of sustenance.
    • In Voyager:
      • The Nebula Creature from "The Cloud", a massive organism that the Voyager crew mistake for a nebula.
      • The Telepathic Pitcher Plant from "Bliss", a giant space monster that mind-controls the crews of passing starships to fly into its mouth so that it can eat the ship whole.
      • Bevvox from "Think Tank", a huge organism which previously wandered the stars by itself for thousands of years. Unlike some of the others listed here, instead of bragging about how ancient it is, it's apparently sensitive about its age.

  • Classical Mythology:
    • Many of Echidna's monstrous children such as Cerberus and the Hydra are these.
    • Similarly, there was originally only one Pegasus, born from the blood of Medusa.
    • The Minotaur. Most versions have a bull's head, with horns, hooves instead of feet, hands as hard as horns with a bull's strength in striking, and a taste for raw flesh. It was uncontrollable and had to be imprisoned in Crete's Labyrinth -which makes the pictures of him with the ring in his nose rather odd.
    • The Chimera, a three-headed female monster that was part goat, part snake, part lion, with a head for each and breathes fire. It terrorized Lycia as some sort of ancient Kaiju until it was slain by Bellerophon.
  • The Phoenix — the western one — was the only member of its species. "As singular as the phoenix" was a common comparison.
  • Most of Loki's offspring in Norse Mythology including the giant wolf Fenrir, the giant Snake Jörmungandr and the half-humand half-corpse Hell.

    Tabletop Games 
  • In early editions of Dungeons & Dragons, any creature with a Frequency of "Unique" was this trope, as there was only one of them. Many of them aren't actually species unto themselves, such as deities or Demon Lords And Arch Devils, but some were, such as the tarrasque.
    • The fluff indicated this for the Tarrasque in later editions, as well, with the crossover-relevant proviso that unique means per world, not for the entire multiverse (Spelljammer had an apparent exception to that as well — a world crawling with Tarrasque-like beasts... that are docile lithovores. It is theorized to be the Tarrasque homeworld, and the native state of the being when not exposed to other atmospheres).
    • For a given definition of species, Andres Duvall from Ravenloft might qualify, being a Bard lich. His existence is entirely by accident, having tried to use a potent spell book as shield against a Lightning Bolt spell. Not only is he unique in having become a lich without actually dying (he's still undead, he just never went through the process of normal death), but also in being a Bard, since only classes with much stronger magic than that can become liches via conventional methods.

  • BIONICLE, taking place in an artificial world, has quite a few of these, though only a few, like Artakha, Karzahni, and Tren Krom, are confirmed as only having one member. Can also apply to mutants like Voporak of which only one was made, but using species that have many members. A non-sentient example is the Rahi Nui.

    Video Games 
  • Bloodborne: every single one of the Great Ones apart from Amygdala (there are several Lesser Amygdala lurking in Yharnam). While they'll all referred to under that term, "Great One" is just a general descriptor rather than a species, and it's explicitly noted that each Great One is unique and unlike the others (their forms vary from a large brain with arms to a formless energy being to a three way cross between a spider, human and an octopus). What appear to be Mini Mook spawn of some of them (like Rom's spiders or the mermaid-like creatures surrounding Kos) are actually corrupted humans, not their offspring. This is actually a major plot point: the Great Ones all desire children, but have no common mates to reproduce with. This leads them to some pretty extreme measures.
  • Pokémon has a number of "legendary" and "mythical" Pokémon who are depicted as singular creatures, though it's sometimes unclear if there's only one ever, or if they're simply rare and limited in number. Some forms of Pokémon media even contradict each other, such as showing multiples of supposed one-of-a-kind legendaries; but in game mechanics, most are defined as genderless and incapable of breeding (under the player's control, anyway):
    • A number of Pokémon are on the level of demigods and almost certain to be one-of-a-kind: Groudon, Kyogre, Rayquaza, Regigigas, Arceus, Xerneas, Yveltal, Alola's "Tapu" guardian deities (Tapu Koko, Tapu Lele, Tapu Bulu, and Tapu Fini), Necrozma, and Paldea's "Treasures of Ruin" (Ting-Lu, Chien-Pao, Wo-Chien, and Chi-Yu). Zygarde might also count depending on how you define "single specimen".
      • There are other legendary Pokémon that are considered godlike, but it's more ambiguous if there are more than one of them or not. For instance, Eternatus is a Draconic Abomination powerful enough to qualify, but explicitly alien so there may be more out in space.
      • As of Pokémon Legends: Arceus, it is revealed that Arceus itself can grant anyone it deems worthy enough a small "fragment" of itself so it can inhabit the world it created. This may imply that all instances of it being owned by a trainer are also "fragments" of the one true Arceus.
    • There are also a number of cases where these "god" Pokémon made unique creations in some way or another: Ho-oh resurrected and transformed three unknown Pokémon into Raikou, Entei, and Suicune, Arceus directly created Uxie, Mesprit, Azelf, Dialga, Palkia, and Giratina (though it is known to make seconds of the latter three... but according to Word of God it has to recreate the world from scratch to do so), and an unnamed dragon split itself into Reshiram, Zekrom, and Kyurem. Regigigas is also believed to have built the other "Regi" golems, but it's implied that it made multiples of each.
    • Another group don't necessarily have the devastating power that preclude there being more than one, but are treated as singular figures of legend akin to Robin Hood and King Arthur: Celebi, Jirachi, the "Three Musketeers" (Cobalion, Terrakion, and Virizion), some genies (Tornadus, Thundurus, Landorus, and Enamorus), Zacian, Zamazenta, Calyrex and its steeds Glastrier and Spectrier, and Ogerpon and the Loyal Three (Okidogi, Munkidori, and Fezandipiti). There could quietly be at least a few of each, but the stories don't treat them that way.note 
    • You've also got one-off results of human experimentation: Mewtwo, Genesect, and Magearna. There's also Type: Null/Silvally, which is a semi-aversion — only three specimens exist; one is owned by Gladion, one goes to the Sun and Moon player character, and the third remains unaccounted for. Though as of the following game, the Type: Null research was stolen and at least a fourth one was made, being granted to the Sword and Shield player character.
    • There are also a few definite aversions:
    • While distinct from Legendary Pokémon, the Ultra Beasts in Pokémon Sun and Moon are another aversion, since multiple specimens of each one are seen/encountered at various points. Of course, they have no real "legend" and are simply Pokémon which hail from a completely different dimension. Solgaleo and Lunala, despite fitting more under the Olympus Mons umbrella, are considered Ultra Beasts and likewise aren't single specimens either. The one Ultra Beast that is implied to be one of a kind is Necrozma, as it was revered as a Physical God in Ultra Space in its original form, and is even referred to with the name, "The Blinding One".
    • Pokémon Scarlet and Violet feature another aversion in Paradox Pokémon, who are very much like the Ultra Beasts in that they are rare and distinct from normal Pokémon but not unique and just transported from somewhere else (in this case, through time — we think). Even the ones labeled "Legendary", Koraidon and Miraidon, are believed to be simply ancestors and descendants, respectively, of the modern Cyclizar species; and the player encounters more than one. But it gets strange when Paradox versions of existing Legendaries begin to emerge — "Walking Wake" and "Raging Bolt" in particular appear to be reptilian prehistoric versions of Suicune and Raikou, which flies in the face of the existing lore.
    • Scarlet and Violet's DLC introduces a non-Legendary example in a new Bloodmoon variant of Ursaluna. The regular version of Ursaluna is an evolution of Ursaring that existed a few hundred years prior but is practically extinct in the modern day (Ursaring are still around, but the evolution method was lost). Bloodmoon Ursaluna is completely unheard of, and its mutation is attributed to living in a non-native habitat.
    • For completeness' sake, the Pokémon species where we don't really know enough to make a call either way are Mew, Lugia, Ho-oh, Cresselia and Darkrai, Heatran, Shaymin, Victini, Meloetta, Hoopa, Volcanion, Marshadow, and Zeraora.
    • It should be noted that recent games (starting with Omega Ruby and Alpha Sapphire, but hinted at in earlier games) have started implying that each individual playthrough is considered an Alternate Universe in canon — there may be only one Mewtwo in your universe, but there's nothing stopping you from trading for a second one from the next universe over.
  • Pikmin (2001): The Puffstool and Smoky Progg are fought only once and do not appear in the sequel games. The Progg, however, is claimed to be a mutant baby Mamuta by the end credits.
  • Dwarf Fortress: Forgotten Beasts are forgotten remnants from when the gods created a given world. Each one is unique as a result of being procedurally generated, and can vary in terms of limb count, tails, flight, dangerous excretions, and sometimes being made of inorganic things like glass or mist. This gets weird when there is no feasible way for them to survive until they reach you. Creatures made of Mist, Fire, Water, and Dirt are universally killed in one or two hits because the materials they are made of tend to fall apart when attacked; your dwarves tending to punch heads, this causes heads to break apart, killing the creature.
  • Mass Effect: The Thorian is the only specimen of its species shown or mentioned. The fact that there should logically be other thorians is never brought up even once.
  • Sonic the Hedgehog: It's implied that Tails is the only multiple-tailed fox on the planet.
  • In StarCraft II, two unique Zerg entities appear during the Heart of the Swarm campaign. Izsha probably doesn't count so much, given she was mutated from a Terran woman, but Abathur is a totally unique abomination created by the Overmind itself to serve as the chief geneticist for the Swarm; Abathur even notes during the campaign that it would be difficult, if not impossible, for his geno-structure to be recreated and for more like him to be made.
  • Shin Megami Tensei features numerous gods and demons as its Mons, and while lesser demons like the Lilim or Mothmen can exist in quantity, the likes of Zeus and Loki necessarily fall under this trope. Several games enforce it in gameplay, most notably the Devil Survivor subseries where various demons are marked as "Unique" so the player can only have one of them in their party at a time.
  • Torkscrew in Mario & Luigi: Dream Team. This boss... is never really explained species wise, and the game itself actually has characters who wonder what the hell it is and whether things like that live in the desert now. Additionally, you could also say this applies to the Zeekeeper, although that's probably due to him being a deity.
  • Played many ways in different Metroid games. Some bosses, such as the Sheegoth and the Metroids, are mature metamorphoses of a mook species, others like the Ing gain unique forms by consuming technology, some creatures like Thardus are not even classifiable as biological organisms. Then there's Ridley who, despite being revealed to have a metamorphic growth cycle in Other M, has only one known body at a time.
  • Fire Emblem: Awakening has Nah, the half-human, half-Manakete daughter of Nowi, who, according to the Manakete princess Tiki in their support conversations, is the first and (presumably) only non-full-blooded Manakete in the history of Ylisse (and possibly Archanea, as Awakening is a loose sequel of the game). However, this gets averted if the player marries Nowi or Tiki herself.
    • Grima itself is eventually revealed to be a species of its own as well. As the creation of an ancient Mad Scientist that merges human and divine dragon blood with unknown dark magic, Grima is a unique being in the setting. Despite this, it does share a relation with the descendants of its creator who donated his blood to form it, which allows them to use its power to a degree.
  • In Marco & the Galaxy Dragon, Arco—the titular Galaxy Dragon—is the only one of her kind in the entire Milky Way galaxy.

  • Aurora (2019): Kendal is a unique being who is neither a human nor a god, originating as the empty body of a god given life.
  • Darwin Carmichael Is Going to Hell: The Hodag says there's only one of his kind. Apparently you can get some crazy scholarships if that's the case.
  • Fifteen Minds: The dino from Blue Moon Blossom is a sauropod, and the only one of their kind depicted in the comic. In fact, they're also the only non-avian dinosaur in the entire story, adding to their vaguely 'other' feel.
  • El Goonish Shive: The Writer's Block is a block with cat ears, paws, and tail with its name on the side and only one has ever been seen in the comic.
  • Homestuck: While some of the monsters on Jake's island show up in numbers, others appear to have just a single specimen running around.
  • The Inexplicable Adventures of Bob!: Molly qualified until Dean Martin cloned her to make Golly.
  • Zebra Girl: Sandra is the only representative of her race. At least, until Gregory shows up. Hell's inhabitants call her a Nefastis.

    Web Original 
  • Mystery Flesh Pit National Park: The titular Mystery Flesh Pit is not only the only known member of the species Immanis colosseus, it is also the only known occupant of its own phylum - Immanemqa. Emphasis on known. The existence of other flesh pits has been noted to be impossible to rule out, and they're unlikely ever to be found given how deep underground they live. And something that looks a lot like the fossil of another flesh pit or similar organism was photographed by a NASA probe to Venus, which just raises more questions...

    Western Animation 
  • Any Kaiju in The Powerpuff Girls.
  • Most imaginary friends in Foster's Home for Imaginary Friends.
  • Each of the 627 genetic experiments in the Lilo & Stitch franchise (primarily Lilo & Stitch: The Series and Stitch!) and Leroy from Leroy & Stitch though subverted with Leroy if you count the many clones of him made later in the movie.
  • Ben 10: Alien Force: Sugilite, guardian of Petropia, is the only one of his kind, until a sample of his DNA was placed into the Omnitrix, creating Ben's Chromastone form.
  • In Futurama Yivo is the only member of shkler species.
  • In Muppet Babies, Gonzo is often classified as a "weirdo" because no one, including himself, knows what he is.
  • The Hydra and the Sea Serpent in My Little Pony: Friendship Is Magic. The Hydra lives in a swamp inhabited by tiny frogs within walking distance of Ponyville and is more than eager to chase Twilight Sparkle and her friends, yet never seems to stroll over to munch on the happy little ponies. The Sea Serpent is much more friendly, can talk, and is very very Camp Gay, and shouldn't even be able to fit in the tiny river he lives in, let alone find enough food to keep himself going.
  • In Disney Fairies' Tinker Bell and the Legend of the NeverBeast ‘Gruff’ the Titluar Neverbeast is a magical Creature which is one of a kind, he awakens every one thousand years to build four rock towers in order to stop a great storm from destroying pixie hollow
  • Wander over Yonder: While more of Sylvia's species is seen (and she's well established to be a Zbornak) and Commander Peepers is obviously a Watchdog, Lord Hater and just as interestingly Wander himself are as best we know it the only ones of their kinds.
  • In the third season of Jurassic World: Camp Cretaceous the campers learn that Dr. Henry Wu, prior to creating the Indominus Rex, made the Scorpius Rex (aka E750) a far more deadly and unstable hybrid. However despite Wu only creating one this would get averted when they campers discovered that the Scorpius was able to asexually reproduce...

    Real Life 
  • Tales of the Loch Ness Monster. Unless it actually is a type of plesiosaur, if it exists. That would make it a Last of His Kind scenario.
  • Scientists uncover these all the time. Frighteningly, it's often unknown if they are the last of a species wiped out by human activity or the tip of an iceberg that is never uncovered because a second specimen is never identified. A rule of thumb regarding species is that species with a high population are rare, and species with a low population are common.
    • The most extreme example is a bird known by a single wing. It has never been seen since, and it is possible it was a mutation, not a different species.
  • Some long-extinct species are known from only one fossil (hence a single specimen), which can make it difficult to know which features were common to the whole species and which were specific to the organism; for example, the specimen may have had a genetic disorder, or may be younger (and hence smaller) than average. Also, even after other fossils are uncovered, the original discovery may be so iconic that it is forever tied to the species, especially if the original has a name: far more people know about "Lucy" than about Australopithecus afarensis.
  • Several animal hybrids exist that have had only one known representative, such as Motty the half-African/half-Asian elephant calf (deceased) born at Chester Zoo. Most such hybrids arise in captivity, as species that interbreed in the wild tend to do so more frequently than this trope demands.
    • There is one particular reason for this that extends to most of the more exotic hybrids; as animals from one side of the world will never breed even with compatible ones from the other in the wild, such breedings in captivity are often one of a kind because of species viability. As desirable as the traits of a particularly rare crossbreed might be, you would need a huge stock of both species to keep them around, as crossbreeds are usually unviable, or for one genetic reason or another incapable of producing children. Thus, any time one shows up is likely to be the first and last time.
  • The Hong Kong orchid tree is a unique hybrid that has only been found in the wild once in 1880. All of those trees today are artificial clones of the original.

Alternative Title(s): Ecologically Implausible