Single Specimen Species

"But the most wonderful thing about tiggers is... I'm the only one!"

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 World Building, 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.

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.
    • 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. Early English translations state that he was created by the wizard Bibidi, but in the original Japanese version Bibidi only figured out how to imprison him.
      • Now averted, as there's a whole race of Majins that spawned from Buu.
  • 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.
  • In Pokémon many "legendary Pokémon" would count as one of these.
    • The Poké-Gods (i.e. Dialga, Palkia, Giratina, and Arceus) are the only truly "one-of-a-kind" Pokémon. 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.
    • Mewtwo was created by humans and was the only member of his species as his creators were killed and all the research describing his creation was destroyed. That is until the 16th Movie introduced a second Mewtwo that makes it a species of two.
    • 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: Wishmaker and the Best Wishes episode "Wish on Jirachi: The Seven Day Miracle." (Although the existence of two Millennium Comets is harder to explain)
      • In the manga however, it keeps the tradition of only-one species with all legendary Pokémon, with the exception of Deoxys.

    Comic Book 
  • The concept/cosmic entity Dream from The Sandman. 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.

  • 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 this-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 the 2014 remake, he is made to be the last survivor of a race of alpha predators.
  • King Kong:
    • In the original, to their knowledge they never see anything that could possibly breed with it in that island.
    • Peter Jackson's 2005 remake kicks 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 glace, 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 a while 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 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.
  • 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.
  • 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.
  • Adam in The Bible qualified, before Eve entered the picture. God himself too.
  • The Incredibly Deadly Viper in A Series of Unfortunate Events
  • Tigger from Winnie-the-Pooh. He gleefully rejoices in it too.
  • Marko from The Sanguine Chronicles is a half-vampire, half-werewolf… which for reasons outlined in the story, is supposed to be impossible.
  • 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 co-operatively 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.

    Live Action TV 
  • A number of entities and creatures in the various Star Trek series.
    • On The Original Series
      • The creature that was Jack The Ripper. An entity that fed on fear and death, who claimed to be as old as time.
      • The Guardian 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.)
    • On The Next Generation
      • Ronin 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.
      • The "Crystalline Entity" is a space-faring creature that consumes organic matter from entire planets. No other examples of its species were seen (until the MMORPG came out, at least).
    • On Voyager
      • The Telepathic Pitcher Plant, a giant space monster that would Mind Control the crews of passing starships to fly into its mouth so it could eat the ship whole.
      • The Nebula Creature (a massive organism that Voyager mistook for a nebula.)
      • Bevvox, the founder of The 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.
  • 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 dub 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.
  • Many, many monsters of the week on The X-Files and The Outer Limits.
  • Averted 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.

  • Many of Echidna's monstrous children such as Cerberus and the Hydra are these.
  • The Phoenix — the western one — was the only member of its species. "As singular as the phoenix" was a common comparison.
  • 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 horn 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.

    Tabletop RPG 
  • In early editions of Dungeons & Dragons, any creature with a Frequency of "Unique" was this trope, as there was only one of them. Examples included demon lords, arch devils, deities and 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).

    Video Games 
  • There appears to be more legendary Pokémon that are single specimen than the anime does, but it's hard to tell whether most are the only one, period, or just so rare they haven't found a second.
    • A number of Pokémon are on the level of gods and almost certain to be one-of-a-kind: Groudon, Kyogre, Rayquaza, Arceus, Xerneas, Yveltal, and Zygarde; plus Arceus' creations Uxie, Mesprit, Azelf, Dialga, Palkia, and Giratina (though Arceus is known to make seconds of the latter three). You've also got Mewtwo and Genesect, which are one-off bioengineering experiments; and Reshiram, Zekrom, and Kyurem, which are the results of a Literal Split Personality (and the dragon they were pre-split would probably itself land on the list of unique demigod Pokémon).
    • There are also a few definite aversions: Latias is stated not to be one-of-a-kind in one Pokédex entry (and its Spear Counterpart Latios would be the same), Deoxys and Diancie come from rare but repeatable mutations, and Manaphy are known to both hatch from eggs and produce more eggs (though their offspring in captivity are Phione and not more Manaphy).
    • Though, through trading with other games (which are treated as alternate timelines in-universe), you can get every Pokémon-species (even Mewtwo or Genesect) as often as you want, and there is a shiny-version for every species in the game-code, which means there exist two color-variations for every single species.
  • In Pikmin, the Puffstool and Smoky Progg are fought only once and do not appear in the sequel. Averted in Pikmin 2 since any boss can be fought again, even if killed the first time.
    • The Progg, however is claimed to be a mutant baby Mamuta by the end credits.
  • The Nihilanth in Half-Life are similar biologically to other Xen creatures (especially the controllers), but apparently the only one of his species. According to Word of God the Nihilanth's species was systematically hunted down and exterminated by the Combine until only this one remained. Until Gordon killed it, anyway.
  • Forgotten Beasts in Dwarf Fortress 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.
  • The Thorian in Mass Effect was the only known specimen of its species in existence. This is probably a good thing, as it was hostile to most other forms of life and liked to mind-control people through spores. All that's left of it now is its nearly planet-wide root system... hopefully it can't regrow itself from that.
  • It's implied that Tails from Sonic the Hedgehog 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.
  • 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 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, and 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. His consciousness seems to persist between incarnations as a facet of the same psychic power that lets him control the Space Pirates.

    Web Comics 

    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 Lilo & Stitch: The Series and Leroy from Leroy & Stitch
  • 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.
  • 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.

    Real Life 
  • Tales of the Loch Ness Monster. Unless it actually is a type of aquatic dinosaur, 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 common is rare and rare is common, or that there are more species with smaller sample sizes than there are of large known populations.
    • 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.
  • These examples overlap with Last of His Kind
    • Lonesome George, the very last Pinta Island Tortoise.
      • As of 24 June 2012, no longer an example, sad to say. R.I.P., George.
    • Hyophorbe amaricaulis, the Loneliest Palm. This is a species of palm tree with only one known member in the world, in a garden in Mauritius.
    • The 52-hertz whale, the Loneliest Whale. Its actual species is unknown, but it has a unique song, and has never gotten a response in the years researchers have been recording it.
  • Several animal hybrids exist that have had only one known representative, such as Harjeeven 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.

Alternative Title(s): Ecologically Implausible