Descriptively Named Species

An alien species has a conveniently descriptive name based on their looks, behavior or blatantly obvious evolutionary provenance. The species is exactly what it says on the hat.

This can be:
 * Justified Trope in that the aliens are named by outsiders, although, as an intelligent alien species and possibly a sovereign alien nation you might want to inform the Earthlings that you do not much care for being referred to as Foul-Smelling Space Devils. However, sometimes the name can become an Appropriated Appellation. Another version is that the aliens' species name is automatically translated for human ears.
 * Inexplicably so if the aliens actually refer to themselves, if not as Foul-Smelling Space Devils, as Stinkdevilonians calling attention to the writer's inability to come up with an alien-sounding name or, alternatively, their Anvilicious approach to characterization.

Goes very well with Planet of Hats and Space Romans and might overlap with Named After Their Planet if the naming convention extends to the homeworld as well. For some reason, felinoid and reptilian aliens are all but guaranteed to have a descriptive name.

Please note that this trope can be used by aliens on humans as well.

Comic Books

 * Watchers, symbiont and Brood in Marvel Comics.
 * Guardians Of the Universe (Also called Oans).
 * The rather aggressively expansionistic Reach.
 * The observant Monitors of DC Comics.

Film

 * While they likely do have an actual name for their species, the Prawns from District 9 arguably count. A justification is given in-universe, that they are bottom-feeders and scavengers.
 * The second Men in Black film has a gag where K is unsuccessfully fighting a particularly tough alien when J shouts to him "He's a Ballchinian!" K pulls down the alien's collar and reveals a scrotum dangling from his chin, which he promptly kicks.
 * Star Wars
 * The quite squid-like Admiral Ackbar is a Mon Calamari.
 * The Nosaurians are really yes-Saurians.
 * Sand People. They live in the desert.
 * Both the name "Sand People" and the alternative name "Tusken Raiders" are explained in the Expanded Universe.
 * The Frost Giants from the Thor film fit this pretty well: giant alien beings made of frost.

Literature

 * All over the place in the works of Alastair Reynolds: Inhibitors, Nestbuilder, Pattern Jugglers, Shrouders, Scuttlers, Fountainheads, Musk Dogs, Smiling Ones, to name just a few.
 * Arthur C. Clarke: The aliens in the Odyssey Series are simply called "the Firstborn," since they are Precursors. The ones in Childhood's End are called the Overlords, because they're in charge of Earth.
 * In The Culture series, there's a race called the Affront who are humorously sadistic. Justified though in that this is an insult they were called by other groups, which they took as a compliment and appropriated.
 * Marion Zimmer Bradley's Darkover series has the Catmen, who are human-sized humanoid cats.
 * Pierson's Puppeteers in Larry Niven's Known Space stories. They have two heads on stalks that look like hand puppets.
 * Lampshaded in Last Son of Krypton. Luthor has been taken captive by space aliens who communicate to him using a universal translator. The aliens explain that it translates into whatever word he expects to hear. Thus: "As I referred to you before, you are a Terran. I am a bug-head. The creature who just addressed you is a vulture-face."

Live Action TV

 * Doctor Who
 * The Doctor himself is a Time Lord.
 * Sea Devils, who sometimes call themselves that despite the name having been coined by humans.
 * Adipose.
 * The Abzorbaloff. Absorbs people.
 * Terry Nation had a habit of doing this with his Doctor Who stories. To give two examples (both from The Chase) the planet Aridus is a desert world and the planet Mechanus is inhabited by robots.
 * Aridus and Mechanus are extreme examples, since Aridus was once a lush world and Mechanus wasn't supposed to be taken over by the Mechanoids. One Doctor Who Magazine article referred to "the charming habit human colonists have in Terry Nation stories of naming planets after what's going to happen to them."
 * The firey (Pyro) villains (Vile) of "The Fires of Pompeii" are the Pyrovile.
 * The Cybermen of course. Alien Humans who became cyborgs.
 * The Daemons encountered by the Third Doctor.
 * The reptilian Draconians.
 * The Forest of Cheem, tree-people.
 * The Futurekind.
 * Blood-drinking Haemovore.
 * Ice Warriors.
 * The Cheetah People in Survival.
 * The Cat People in "New Earth" and "Gridlock".
 * Star Trek used to be very fond of this and typically falls to the "inexplicable" side.
 * The Romulans and Remans come from Romulus and Remus, respectively. When they're introduced in the Prequel show Star Trek Enterprise, the uneducated crew of Enterprise is apparently not surprised that those aliens are named for mythological figures from Earth. The prequel could have easily turned this trope around by having humans name the Romulans "Romulans".
 * Non-canon novels establish that both the Romulans and the Vulcans really have different names.
 * Avoided by retcon for the Klingon homeworld whose spelling was changed from "Kronos" to "Qo'noS" to imply that it just happens to sound similar to the child-eating titan from Earth mythology.
 * The Grazerites from Grazer have evolved from grazing animals. Yes.
 * The Saurians from Sauria look like dinosaurs.
 * The Caitians from Cait are humanoid cats.
 * Denebian Slime Devils.
 * Star Trek the Next Generation: in "Home Soil" the alien crystalline life form calls humans "ugly bags of mostly water."
 * The Bynars of Star Trek the Next Generation who live in pairs.
 * Star Trek Voyager: The Hierachy. Low-ranking Hierachy individuals are not allowed to do anything out of the routine without consulting their superiors first.
 * Also, The Swarm.
 * Mocked on Supernatural: Dean comes across a new type of demon that no one has ever seen before, so Bobby says that Dean gets to name it. Dean calls them Jefferson Starships, "because they're horrible and hard to kill."

Role Playing Games

 * The dragon-like Dracons of Wizardry games. The rat-like Rattkins count as well as the feline Felpurrs, the canine Rawulfs and the Tarantula-like T'Rang.

Tabletop RPG

 * Traveller alien races.
 * Aslan: feline-like humanoids, named either for the Turkish word for "lion" or the character Aslan in the Chronicles of Narnia.
 * Vargr: wolf-like humanoids, named from the Old Norse word meaning "wolf".
 * The K'Kree are a partial example. Their nickname is "Centaurs", because they appear very similar to the centaurs of Greek Mythology.
 * The Hivers live together in underground nests.
 * Dungeons and Dragons
 * The dinosaur-like Saurials in 2nd edition.
 * Women who could turn into swans: Swanmays of 2nd edition.
 * The dragon-like Dragonborns of 4th edition.
 * The misshapen Mongrelmen of 2nd edition.
 * The living plant siege engines called Battlebriars.
 * The shadowy, sneaking Dark Ones.
 * The Devourers who eat souls.
 * The Displacer Beasts, who can make themselves look like they were somewhere else.
 * The telepathic, mind-controlling Mind Flayers.
 * The speedy Quicklings.
 * Warhammer 40000: the various Tyranid organisms' name were given by the Guardsmen fighting them. Hence Ripper swarms, Gargoyles, Carnifexes (butcher in fake Latin)...
 * Strangely used by the Tau in that their vehicles are all named after Earth fish (Piranha, Devilfish, Hammerhead...) and use Greek-letter callsigns.
 * Explained in the codex as being Imperial Reporting Names, as the Tau's own naming scheme is ridiculous and alien.

Video Games

 * The Ravagers of Earth Defense Force 2017 and Earth Defense Force: Insect Armageddon. Amusingly, they were dubbed Ravagers before their penchance for ravaging became apparent.
 * Contrary to what their name might suggest, Metroid's Space Pirates are not simply a band of space-faring pirates but a full-blown species. Though they are never shown speaking, they even seem to refer to themselves as "Space Pirates" in their logs, (though this may just be Samus's suit translating anyways). They are lead by a space dragon, a giant brain, and a colossal space lizard, all of whom may or may not have a biological relation to the Space Pirate Mooks.
 * In the Myst sequel Riven, the creatures called wahrks are a mixture of whales and sharks. It's implied that this name for them was developed independently by a race who had never heard the English language.
 * Collectors, Reapers, and Keepers from Mass Effect. It should be noted that none of the three species call themselves the names; Collectors and Keepers don't speak and Reapers disdain the title given to them.
 * The Collectors and Keepers are named as such by the Citadel races.
 * The Hivers in Sword of the Stars, which is a name used by humans and not by the species itself (their name, translated to English, means "The Children"). Also the Zuul, who are a descriptively named species in Liir speech: The word is a root of the Liir term for "abominable". The Zuul have no name for themselves, their telepathy doing odd things to their sense of personal identity, and probably don't care what others call them.

Web Comics

 * Subverted in Starslip: the ship visits an alien race called the Oculons, who have no eyesight. Vanderbeam bemoans the irony of their name considering they can't see, and one of them tells him, no, that's not what they call themselves, humans just named them that because their planet looked like a giant eye.
 * Schlock Mercenary has an amphibious species called the Tohdfraugs.
 * And Schlock is a "carbo-silicate amorph". In this case it kind of makes sense, because his species didn't evolve naturally and give themselves a name; they were originally data storage units which happened to spontaneously gain sentience (in a very literal sense, Schlock is all brain).

Western Animation
"What are you gonna do? Shoot us?"
 * Both alien species and individuals in Ben 10 have descriptive names, for example, Galvans for Upgrade's species, Vulpimancers for Wildmutt, and Florauna for Wildvine.
 * The lobster/crab-like Decapodians of Futurama.
 * There would actually be quite a few examples: the Amphibiosans (amphibians), the Brain-Spawn (floating brains), the Amazonians (a One-Gender Race of gigantic women), etc. The Nibblonians also sort of count, using that name on the grounds that they're "like Nibbler." (Presumably they have their own name that would take longer than the age of the universe to pronounce.)
 * Into The Wild Green Yonder has the (unsurprisingly)extinct striped biologist taunters, striped animals that taunt biologists.


 * Thundercats 2011, despite being set on an alien planet, simply calls its Petting Zoo People by obvious names: Cats, Dogs, Lizards and so on, but gets a bit more creative with more fantastic races, like Petalars, Giantors and Cute Machines teddy bears the Ro-Bear Berbils.
 * Invader Zim gives us the Slaughtering Rat People of Blortch. They're mostly a one-off gag for the Tallest to 'dispose' of the unwanted Invader Skoodge, until Skoodge against all odds succeeds at being the first Invader to conquer his assigned planet.