Robots and other fully mechanical entities can be found here.
As with all Doctor Who characters, they appear not only in the televised adventures, but also in the Expanded Universe branches.
First Doctor era debut
Thals (First, Third and Fourth Doctors)
Thals were one of two sapient races native to the planet Skaro. The other race were the Kaleds, who eventually became the Daleks after a long and bitter war against the Thals.
- Actual Pacifist: After a thousand years of war, they refuse to fight the Daleks again.
- Arch-Enemy: With the Kaleds. The war between the two races lasted a thousand years. They are also sometimes this to the Daleks, but far less so than the Doctor.
- Beauty = Goodness: The Thals resemble blond humans and are therefore good. The Daleks are blobs in metal tanks and are therefore evil.
- Human Aliens: Just like the Kaleds, they are visually indistinguishable from humans and Time Lords.
- Light Is Not Good: During the War, the Thals had blond hair, wore western-style green uniforms and generally looked like the Anglo-American good guys to the Third Reich-esque Kaleds, but were just as savage and genocidal as their enemies.
- Not So Different: Genesis of the Daleks shows that the Thals could be just as cruel and bloodthirsty as the Kaleds. However, by the time of The Daleks, they've become pacifists. By Planet of the Daleks, as pictured, they've regained a willingness to fight when necessary.
- People Of Hair Colour: The Thals have blond hair and light eyes, in contrast to the brunette hair and dark eyes of the Kaleds. Ironic, considering the Kaleds are very much Space Nazis.
- Took a Level in Kindness: Originally they were just as bloodthirsty and evil as the Kaleds, but the effects of the war caused them to realize the errors of their ways and they became pacifists ... until the Doctor convinces them otherwise.
- What Happened to the Mouse?: They haven't been seen (chronologically) since "Planet of the Daleks", and it's unknown what happened to them during the Time War. The fact that Skaro has a disturbing tendency to be blown up and then reappear in space doesn't inspire much confidence in their survival.
Voord (First Doctor)
A race of semi-aquatic, wetsuit-wearing assassins who have attempted to invade many oceanic planets in the past, they menace the Doctor and his companions in "The Keys of Marinus".
- Arc Welding: The Sixth Doctor comic "The World Shapers" claims that the Voord species eventually evolve into the Cybermen. A throwaway comment in "The Doctor Falls" confirmed this, though made it explicit for the first time that they were one of many origins of the Cybermen.
- Fish People
- Knife Nut: They're armed with deadly knives.
- People in Rubber Suits
- Professional Killer: The Voord make excellent assassins.
- Submarine Pirates: The Voord travel around in small, one-man barges and in larger submarines.
Sensorites (First Doctor)
A telepathic humanoid race native to the Sense Sphere. Appeared in "The Sensorites".
- Ditto Aliens: They themselves cannot effectively tell the differences between each other without first having become familiar with them, and relies on sashes and other decorative garbs to identify important individuals.
- Telepathy: They communicate with each other if they're not close to each other.
- Klingon Promotion: If any of the Elders die, they will be replaced with another one who is next to the rank.
- Weaksauce Weakness: The race is prone to darkness and loud noise.
- Yellow Face: They're based on Chinese Communists.
Zarbi (First Doctor)
Giant alien ants from the planet Vortis. Appeared in "The Web Planet" and have shown up in the expanded universe a few times since, usually as a punchline.
- Anti-Villain: The Zarbi are actually being brainwashed by the Animus.
- Badass Adorable: In their larval form, Zarbi are strangely cute, but can fire a deadly venom.
- Big Creepy-Crawlies
- Bug War: Uniquely, a war between two different factions of bugs. The ant-like Zarbi and the Menoptera, a race of butterfly people.
- Insectoid Aliens: Planet Vortis is full of them. The Doctor and his companions are the only non-insects in the entire serial.
- Meaningful Name: Zarbi is French slang for "bizarre".
- People in Rubber Suits: Really obvious. A rather infamous example, meaning the Zarbi are somewhat of a joke among old-school fandom.
- Running Gag: Whilst the Doctor tangles with formidable foes such as the Daleks, the Cybermen and the Master, Iris Wildthyme keeps running into the Zarbi.
Drahvins (First Doctor)
Beings from the Planet Drahva. They have very few men.
- Absolute Xenophobe: Maaga and by implication all the other upper-caste Drahvins.
- Ace Custom: The Drahvins are so wedded to their caste system that they self-destructively only give their leader caste the good weapons.
- Ambiguously Human: It is unclear whether the Drahvins are human-looking aliens or a human colony that went in a really extreme cultural direction. Maaga refers to herself and her people as "human" or "human beings" several times, but this could just be translation convention given that it's in the context of "sentient beings deserving of life".
- Bad Boss: Seems to be required by Drahvin law and/or custom.
- Beauty = Goodness: Defied.
- Brainless Beauty: The barely sentient Drahvin clones.
- The Cameo: River Song namedrops the Drahvins as members of the Alliance in "The Pandorica Opens".
- Evil Cannot Comprehend Good: The Drahvins can't understand self-sacrifice.
- Fantastic Caste System: The Drahvins have a caste system based on social insects, of female leaders, female workers, and a few males kept solely for the female leaders to sexually reproduce.
- Lady Land: On the planet Drahvin, women dominate the planet. A few men are kept, presumably for breeding, while the rest are killed. Oddly, Maaga doesn't immediately understand when Steven asks her if all the inhabitants of her planet are women, perhaps demonstrating how utterly insignificant and out of mind the men of Drahvin are.
Second Doctor era debut
Macra (Second and Tenth Doctors)
A race of enormous crustaceans who fed off gases that were poisonous to most other species. The Second Doctor first encountered them when they had enslaved a human colony. The Tenth Doctor later discovered a new breed of Macra living under New New York.
- Anti-Villain: In a way. In "The Macra Terror", they only enslaved the colonists because the humans had colonised the Macra home world without asking (assuming of course, it is the Macra home world). In "Gridlock", they're merely non-intelligent animals who are defending their territory.
- Deadly Gas: Their primary food source.
- Evolutionary Levels: After billions of years, the Macra the Tenth Doctor encounters on New Earth have devolved from sapient beings to mindless beasts.
- Giant Enemy Crab: Big enough to crush cars in their pincers.
- Long Bus Trip: Forty years between "The Macra Terror" and "Gridlock".
- Villain Decay: Invoked. After a few billion years, the Macra devolved into a much less intelligent form, so instead of being invisible puppet masters, they're just scavengers living off car fumes.
Ice Warriors (Second, Third, Eleventh and Twelfth Doctors)
Voiced by: Nicholas Briggs (2013)
A race of reptilian aliens who come from Mars, the Ice Warriors were the fourth species of big bads in Doctor Who resulting in several appearances throughout the Second and Third Doctor eras... but they basically vanished with the end of the Third Doctor's run on the show in 1974 (around the time that space probes in Real Life proved Mars to be barren). Efforts were made to bring them back in the original series from time to time but the final attempt was scheduled to be in the 1990 season of Doctor Who... and the show was canned/put on hiatus in 1989.
- Animated Armour: They find leaving their armour deeply shameful, but if they are forced to do so they can remote-control it.
- Big Bad Ensemble: Before they vanished, these guys were the fourth biggest alien villains for the Second and Third Doctors.
- Cyborg: According to "Cold War", they're this; it helps them deal with Mars' freezing conditions.
- Disproportionate Retribution: By their code, an attack on one Ice Warrior is an attack on all of them. And they respond in kind, even if the attack doesn't even harm the warrior in question.
- HeelRace Turn: Their first two serials have them as the villains, but since Jon Pertwee's first brush with them they've alternated between friends and foes (one of them even became a companion in the Expanded Universe).
- Last of Their Kind: Since Mars is somewhat inhospitable to them after some unspeakable event in their past, it's a little hard for the species to continue especially when they have a nasty habit of getting wiped out whenever they encounter the Doctor. To make matters worse, the Expanded Universe puts the Doctor essentially at fault for said unspeakable event. Whoops. This appears to have been retconned as of "Cold War", with the Doctor saying Martians survive on other planets, and a Martian ship appearing at the episode's end. "Empress of Mars" reveals the survivors lasted on the dead world for some time in suspended animation before being evacuated by a fleet from Alpha Centauri.
- Logical Weakness: As Ice Warriors used to a cold environment, they are vulnerable to intense heat.
- Mighty Glacier/Fragile Speedster: Both in "Cold War", depending on if they are in or out of their armour. Since they can remote control their armour, they can even fill both roles at once. However, for cultural reasons they remain in their armour.
- Monster Lord: Their leaders are smaller, slimmer and less heavily-armoured than the usual soldiers. They are often referred to in fanon as "Ice Lords", although this is never used in on-screen dialogue.
- New Neo City: Episodes set in the future usually have them living on a planet called New Mars, Neo Ares or Nova Martia.
- Oh My Gods!: They tend to swear by "the moons" (Phobos and Deimos).
- Proud Warrior Race:
- Subverted in the Doctor Who New Adventures novel The Dying Days, where the Ice Warriors encountered there claim to be this but are psychotic monsters.
- Played Straight in "Cold War," where the Doctor appeals to Skaldak's honor in an attempt to stop him from triggering a nuclear war on Earth.
- Played Straight again in "Empress of Mars", where they were only fighting because the humans attacked them first. After the commanding officer saves their queen from a Jerkass soldier trying to hold her hostage, he offers to let her execute him in return for letting the other soldiers go free. She's so impressed with his courage that she not only agrees, but spares his life, on the condition that he swears loyalty to her and the Ice Warriors. He agrees.
- Put on a Bus: They basically vanished completely after 1974, but returned in the revival with 2013's "Cold War" and 2017's Empress of Mars.
- Red Eyes, Take Warning: Their armour has red-tinted lenses.
- The Reptilians
- Space Romans: Bill Potts compares them to Vikings after hearing the Doctor's description of them, to which he agrees.
- Sssssnaketalk: They often speak like this due to them being reptilian.
- Super Soldier
- Worthy Opponent: This is their view of the Doctor, especially in the Expanded Universe. "The Slow Regard of Silent Stars" mentions that they even gave him a Red Baron as a term of respect. The Doctor always has enormous respect for them and their culture, even when going up against them.
- Zombie Gait: This, combined with their constant shallow breathing, gives the impression that our heroes are in fact being chased around by overweight smokers. They feel compelled to sprint from them anyway.
- As it turns out, this is down to their armour. Out of it, they are terrifyingly fast. Fortunately, Ice Warriors see leaving their armour as deeply dishonourable... which means that when one does leave it, the situation is desperate, both for the Ice Warrior and their unfortunate opposition.
Krotons (Second Doctor)
A crystalline race of aliens. Along with the Quarks, the Krotons are villains from the Sixties who are fondly remembered for having endearingly silly designs. They are also notable for being the first in a long line of Doctor Who monsters created by Robert Holmes.
- Beware the Silly Ones: In the Eighth Doctor Adventures novel Alien Bodies, a lone Kroton destroys an entire battleship full of Daleks.
- Mechanical Lifeforms: The Krotons resemble robots made of crystals.
- Our Monsters Are Weird: They have a Tin-Can Robot appearance but are actually sapient tellurium crystals that are technically immortal, with the closest thing to death that they have being to "exhaust" (turn into a gaseous state and leave their vessel). The implication (made explicit in the books) is that they can possess any machine into becoming their body. They are blind, power their machines with mathematical aptitude, Mind Rape people in order to get the power, breathe fluid through hose lines in their chest, and have inexplicable accents.
- Starfish Aliens: Living crystals who resemble robots and power their spaceships with mental energy. Even by Doctor Who standards, they're pretty weird.
- Weakened by the Light: They have poor eyesight in daylight and so have trouble moving around.
Third Doctor era debut
Autons (Third, Ninth, and Eleventh Doctors)
The Autons are evil living plastic servitors that are controlled by the squid-like Nestene Consciousness. Their best known trick is posing as shop dummies and bursting out of high-street windows, although their second appearance had them trying to kill people in increasingly bizarre ways. They don't need to be humanoid, either; any seemingly inanimate plastic object will do chairs, toys, even a trash can. The Consciousness can also create more sophisticated "facsimiles" (referred to as "Nestene Duplicates" in the revival) that perfectly mimic the appearance of others... and may even believe their own cover story.
- Animate Inanimate Object: So long as it's made of plastic, the Nestenes can bring it to life and kill people with it.
- Arm Cannon: Well, hand cannon.
- Breakout Villain: One of the original run's most iconic monsters, despite only appearing three times. The image of mannequins stepping out of shop windows and attacking was vivid enough for them to get into the revival's first episode.
- Capitalism Is Bad: Shops full of killer aliens? Yeah, that symbolism is pretty obvious.
- Everything Trying to Kill You: As the Third Doctor's tenure was largely confined to the Home Counties in the present day for budget reasons, the Autons inaugurated the grand old Doctor Who tradition of everyday objects trying to kill you.
- Hive Mind
- Immune to Bullets: The original versions helped inaugurate a long tradition of UNIT's guns being utterly useless against the threat of the week.
- Manchurian Agent: Some later-model Autons come with fake memories.
- May Contain Evil
- Mooks: The Autons are the Nestene foot-soldiers, doing the work disposing of any threat, since the Nestene lack the mobility to do so themselves.
- Murderous Mannequin: The Autons are most infamous for the ones in the form of store mannequins coming to life, bursting through windows and attacking and killing people.
- Ridiculously Human Duplicates: Some of them are created as Uncanny Valley versions of humans (Auton!Mickey) but others are so indistinguishable from human that they even believe their own cover stories (the "Romans" and Auton!Rory).
- Step Three: Profit: In the Doctors Revisited Jon Pertwee special, Steven Moffat felt the Autons' original invasion suffered from this.Steven Moffat: It's a genius idea. Conquering the world with shop dummies! For no particular reason other than it's really scary. What was the plan, exactly? We're going to conquer Earth, by planting... shop dummies in windows.
Steven Moffat: Terrifying idea. Brilliant. And of course, like all great Doctor Who ideas, completely bonkers.
- Uncanny Valley: In-universe. Autons often attack and replace targets, but they tend to miss certain details. Like how human skin isn't that smooth and shiny. Averted with the ones in 2010, who look and act completely human until the moment arrives.
Primords (Third Doctor)
Mutated human beings, created as a result of exposure to ooze emitted by Project Inferno, an attempt to drill through to the Earth's core. At first the change manifested itself in the form of discoloured skin, violent behaviour and the body generating intense amounts of heat, but warmer conditions would cause the transformation to progress to its final stage, causing the victim to vaguely resemble an ape or werewolf.
- Achilles' Heel: Were very vulnerable to cold, which was the only surefire way of killing them. Well, that and throwing them off a tall building, which isn't always feasible.
- Axe-Crazy: At first, anyway, with people in the early stages of the transformation being inclined towards trying to beat people to death, either with their bare hands or whatever blunt instrument they have to hand. It actually seems to lessen after the transformation completes, when their MO switches more to actively trying to infect others.
- Immune to Bullets: Can easily shrug off multiple gunshot wounds right through the heart, just so long as that isn't combined with any sudden drops in their body temperature.
- Painful Transformation: Most of the transformations don't seem overly painful, but when the process is accelerated either by greater ambient heat (in the case of the parallel Benton) or exposure to a large amount of the ooze (as with Professor Stahlman), the change is depicted as being much more painful.
- The Virus: The first few Primords in either universe were created by exposure to the green ooze, but after that were capable of infecting others simply by touch.
- Was Once a Man: All of the victims started out as humans, before being infected either by ooze or other transformed people.
Axons (Third Doctor)
The Axons were part of a gestalt entity known as Axos that came to Earth to devour all of our planet's energy in the serial "The Claws of Axos". They were defeated by the Third Doctor and UNIT. The Axons have also shown up in Big Finish Doctor Who (where they fought the Sixth Doctor) and the comic strip of Doctor Who Magazine (where they battled the Eleventh Doctor and Amy Pond in Japan).
- Beauty = Goodness: Subverted. They appear as golden angelic humanoids but turn out to be monstrous.
- Glam Rock: The aesthetics of glam rock had a very big influence on the look of the Axons. It was the early Seventies, after all.
- Hive Mind: The seemingly individual Axons are all part of the same entity.
- Light Is Not Good: Gold and orange are the Axons' primary colour palette and they turn out to be evil.
- Organic Technology: The spaceship they arrive to Earth in. Considering that even the ship is part of the Axos hive mind, this makes sense.
- Trojan Horse: The Axons provide the human race with an alien fuel called Axonite, seemingly to help us with our energy crisis but actually to destroy us.
Ogrons (Third Doctor)
Ogrons were strong, ape-like humanoids of limited intelligence, typically used by other species as mercenaries. They were most often employed by the Daleks. They live in scattered communities on an unnamed planet on the outer fringes of the Milky Way, far from the central spaceways. The dominant lifeform on their home planet is a giant slug-like lizard named the Eater, and the Ogrons both pray to and are preyed on by it.
- Alien Hair: Of the incredibly recessed hairline variety.
- Dumb Muscle: Ogrons are very strong and very stupid.
- Killer Space Monkey: They're extremely strong and brutal.
- Mooks: They typically show up as expendable goons for the Daleks and the Master.
- Servant Race: Are this to the Daleks. However, IDW Comics seems to show them more as Punch-Clock Villains.
- Shout-Out: The name may be derived from the mythological creatures ogres.
- Space Orcs: They're large, black-to-purple-skinned caveman-like aliens mainly noted for their stupidity and their aggressive natures. Most live primitive lives on their homeworld; the ones seen on other planets are typically mercenaries and thugs under a villain's employ.
Peladonians (Third Doctor)
The Peladonians (or Pels) were a race of near-humans native to the planet Peladon who retained a feudal culture.
- Alien Sky: Their planet was known for being especially stormy. Dangers from the wind and rain were constant.
- Feudal Future
- Human Aliens
- Skunk Stripe: One of the few ways to tell them apart from humans is the burgundy streak through their hair.
- Yellow Rocks: Their planet has a mineral called trisilicate (Not to be confused with magnesium trisilicate). Word of God says Barry Letts took the name "trisilicate" from a list of ingredients on the back of a tube of Boots brand toothpaste.
Drashigs (Third Doctor)
Draconians (Third Doctor)
The Draconians are an extraterrestrial race of reptilian humanoids. In later interviews, Jon Pertwee cited the Draconians as his favourite of all the monsters he had encountered during his time as the Doctor.
- Alien Hair: Draconians have beards, but atop their heads they've got a ridged crest instead of humanoid hair.
- Fantastic Slur: Some humans call them "Dragons".
- Feudal Future: The Draconian Empire was a vast spacefaring feudal civilisation centered on the planet Draconia, with a society stratifed along class and gender lines (for example, females were not permitted to speak in the presence of the Emperor) that was bound by a strong code of honour.
- Non-Mammalian Hair: Their beards.
- Reasonable Authority Figure: The Emperor.
- The Reptilians
- Snake Talk: They have a somewhat subdued version of snake talk, mostly hissing if a word ends on an "s" sound only.
- Wutai: Draconia is basically feudal Japan in space with reptile people.
Fourth Doctor era debut
Wirrn (Fourth Doctor)
- Big Creepy-Crawlies: The Wirrn stand at around 6-7 feet tall. Not too shabby for an insect race.
- Body Horror: You slowly and painfully begin turning into one of them once a Wirrn stings you.
- The Cameo: A dead Wirrn has a brief appearance in "The Stones of Blood".
- Dying Race: Their main hives have been wiped out, leaving them desperate.
- Fighting from the Inside: Like many infectious Doctor Who monsters, their victims can fight back with strong willpower and emotions.
- Insectoid Aliens: They resemble enormous wasp/ant hybrids.
- It's Personal: The reason the Wirrn try to devour the remaining humans on Nerva Beacon is because their hives across the galaxy were wiped out by pioneering humans.
- Off-the-Shelf FX: One of the most (in)famous examples in Doctor Who's history. A lot of the Wirrn effects were achieved with green bubblewrap, bubblewrap being a new invention in 1974. The effective acting in "The Ark in Space" goes a long way towards making the effect a bit more believable. This was given a nod in the revival series, when Clara Oswald finds a sarcophagus full of green bubblewrap.
- The Virus: Once they sting you, you begin turning into one of them. The Doctor compares the Wirrn to real life parasitic wasps who lay their young inside caterpillars.
Zygons (Fourth, War, Tenth, Eleventh and Twelfth Doctors)
The Zygons are a race of shapeshifting humanoids. After their planet was destroyed in a stellar explosion, they seek to colonise other planets, including Earth. Thanks to their well-realized design and the fact that "Terror of the Zygons" is considered a classic by the fandom, the Zygons became very popular despite having only one appearance in the original run of the show. David Tennant has named the Zygons as his favourite Doctor Who monsters.
- Always Chaotic Evil: Averted. Most of the Zygons living on Earth just want to live in peace and at worst are Punch-Clock Villains for Zygon High Command.
- Anti-Villain: Their home planet was destroyed, so they understandably seek a new one. Unfortunately, they want Earth, an already-inhabited planet.
- Attack Animal: The Skarasens (as seen in "Terror of the Zygons" and the Tenth Doctor novel Sting of the Zygons) were massive creatures, large enough to crush a human with one clawed foot. They were cybernetically altered to suit the Zygons' purposes. They were invulnerable to any force short of a nuclear weapon. Their skins were highly durable and their skeletons were fused with an extremely tough alloy.
- The Cameo: In "Attack of the Graske" (a Tenth Doctor mini-sode) and "The Power of Three", albeit in human guises in the latter.
- Disintegrator Ray: One application of their ability to shoot electricity from their hands.
- Face of a Thug: Despite their horrendous appearances and hideous-looking faces, most Zygons are peaceful in nature and simply wish to be left alone. This trope is partly downplayed by the fact that Zygons can assume human forms and thus not look so monstrous.
- Fatal Flaw: Their arrogance proves their undoing in "The Day of the Doctor".
- Foreshadowing/Cerebus Retcon: In "The Day of the Doctor", it is revealed that the destruction of the Zygons' homeworld mentioned in their first appearance was in fact an extremely early impact of the Time War on the Doctor's own adventures.
- Long Bus Trip: 38 years between "Terror of the Zygons" and "The Day of the Doctor". The Zygons had, however, had a handful of appearances in official novels and audio plays.
- Organic Technology: The Zygon ship seen in their first appearance. Played with in that while the interior is very organic, the exterior of the ship is a metal hull. "The Zygon Invasion" features a Zygon organic computer that the Doctor interacts with.
- Poisonous Person: They can poison humans with a touch. They also have, as the Tenth Doctor would attest, venom sacs under their tongues.
- Shapeshifter Baggage: Not only can they impersonate humans (who are much smaller than them), Zygons can also shapeshift into other non-humanoid lifeforms such as horses and (maybe) rabbits. In "The Zygon Invasion", the paranoid Colonel Walsh says that "any living thing" on Earth could be a Zygon in disguise.
- Shock and Awe: In "The Zygon Invasion" and "The Zygon Inversion", the Zygons can shoot electricity out of their hands that can disintegrate humans into piles of hair and skin. It's not clear if this is a natural ability or some kind of bio-weapon.
- Stock Ness Monster: One of their Skarasens lived in Loch Ness for centuries and inspired the legend.
- They Look Like Us Now: The Zygons' ability to assume human form is what makes them so paranoia-inducing.
- Underestimating Badassery: Lampshaded in "The Day of the Doctor". Their arrogance meant they never stopped to consider that their own commander might have been killed and subsequently impersonated by Elizabeth I, instead of the other way around.Elizabeth I: I may have the body of a weak and feeble woman, but at the time, so did the Zygon!
- Voluntary Shapeshifting: They have the power to transform and reshape their bodies to impersonate humans and, as seen in "The Day of the Doctor", other non-humanoid lifeforms such as horses and (maybe) rabbits, although they do need to keep the being they're impersonating alive as a genetic and psychic "body print". In "The Zygon Invasion", it's claimed that this condition isn't needed any more; Osgood states that "the rules have changed".
Krynoid (Fourth Doctor)
Carnivorous alien plants with big appetites. First showed up in "The Seeds of Doom" and have popped up in Big Finish Doctor Who a few times since. A Krynoid also faced off against the Eleventh Doctor in the e-book Tales of Trenzalore.
- Alien Kudzu: It infests entire planets.
- Body Horror: Their victims slowly start turning into giant plant creatures.
- Combat Tentacles: As Mary Whitehouse put it: "Strangulation by obscene vegetable matter."
- Green Thumb: Krynoids have the ability to telepathically control nearby plant life.
- Man-Eating Plant: On planets infected by the Krynoid, the plants eat the animals.
- Palette Swap: The Krynoid costumes are just Axon (in their true form) costumes painted green instead of orange.
- Plant Aliens
- The Virus: When a Krynoid lands on a planet, it will consume all animal life to create more of itself.
- When Trees Attack: The Krynoid's ability to control plant life leads to this.
Rutans (Fourth Doctor)
The Rutans (or Rutan Host) were a race of amorphous green blobs who waged war with the Sontarans.
- Arch-Enemy: To the Sontarans.
- Barrier Warrior: The novel, Shakedown says they could also use electrical energy to produce a force field to absorb energy from weapons, though this required great effort.
- Batman Can Breathe in Space: Shakedown says they can survive in a vacuum.
- Electric Jellyfish: Pretty much a space version of this.
- The Empire: The Duran Empire used to rule the entire galaxy until the Sintarans beat them back to the fringes.
- Face Stealer: The Rutan dissects the first two lighthouse operators in order to learn enough human physiology to take the form of Reuben for the final two episodes. Later victims it just kills.
- Forever War: They've been at war with the Sontarans for a long time, and they'll still be at it thousands of years later. From what little we know of their war, the Rutans seem to have the upper hand most of the time.
- The Ghost: They're appeared a grand total of once in the series, compared to their nemesis race. They do a little better in the wider Who media (once in an Eleventh Doctor Adventure game, a very short Story Arc with the Fifth Doctor in Big Finish Doctor Who, etc.), but appear nowhere near as much as the Sontarans.
- Insignificant Little Blue Planet: The Doctor is quite surprised by the Rutans' interest in Earth. It turns out to be fairly mild.Fourth Doctor: Why invade an obscure planet like Earth? It's of no value to you.
Rutan: The planet is obscure, but its strategic position is sound.
- Sickly Green Glow
- Voluntary Shapeshifting: With great effort.
Ogri (Fourth Doctor)
A species of silicon-based lifeforms native to Ogros, which resemble large rocks or menhirs. They can move slowly from place to place, live for thousands of years, and feed on globulin found in blood via touch.
- Bullfight Boss: The Doctor gets one of the Ogri to charge over the edge of a cliff this way, accompanied by Spanish background music.
- Living Statue: Before the Weeping Angels made it cool, no less!
- Golem: The Ogri are a mix of this and Living Statue, since they're part of a stone circle.
- Rock Monster
- Silicon-Based Life
- Starfish Alien
- Stripped to the Bone: The Ogri can do this to anyone who touches them.
Megara (Fourth Doctor)
The Megara are tiny microcellular biomechanical droids also known as "Justice Machines". They take the form of floating orbs, and are charged with upholding galactic laws and regulations. Unfortunately, their rule-obsessed pedantry means that they're more than a little bit trigger happy...
- Amoral Attorney: Even the Megara that's supposed to defend the Doctor pleads the death penalty.
- Everything's Better with Sparkles: The Megara are pretty much just sentient sparkles.
- Judge, Jury, and Executioner
- Rules Lawyer
- Space Police: They uphold Galactic Law.
- Spark Fairy: As seen in the picture, they look like floating sparkles.
- Starfish Aliens: Sentient sparkles. Enough said.
Mandrels (Fourth Doctor)
Large, furry predators from planet Eden. Mandrels have the curious distinction of decomposing down into a pile of white powder after being electrocuted to death: the dangerous, addictive drug vraxoin, which is highly prized throughout the galaxy.
Nimons (Fourth Doctor)
A race of parasitic nomads, the Nimons travel from planet to planet posing as gods to other civilizations. However, the Nimons eventually drain the planet of its life energy and move on to the next world. Their sole appearance on television is "The Horns of Nimon", but the Nimons also made a memorable appearance in Big Finish Doctor Who and were alluded to in the new series episode "The God Complex".
- Evil Sounds Deep: They have deep, booming voices.
- Frickin' Laser Beams: Uniquely, the Nimons fire lasers out of their horns.
- God Guise: Their modus operandi when it comes to their invasion plans.
- Large Ham: "The Horns of Nimon" is so full of hammy acting it would offend Israel, and the Nimons themselves are no exception.
- Life Drain: How they feed. It leaves people, and entire planets, as desiccated husks.
- A Load of Bull: The Nimons greatly resemble the Minotaur of Greek myth.
- Milking the Giant Cow: The actors in the Nimon costumes are really going for it. Oh, and no jokes about "giant cows".
- Red and Black and Evil All Over: Black fur/skin with bright red eyes.
- Unrealistic Black Hole: The Nimons use black holes to power their technology and as wormholes to travel the universe.
Foamasi (Fourth Doctor)
Tharils (Fourth Doctor)
Fifth Doctor era debut
Terileptils (Fifth Doctor)
- Mark of Shame: The Terileptil leader has face markings (which double as a nasty disfigurement) that mean if he goes back to his home planet he'll be killed. It's never specified if this was intentionally done by the authorities, or merely the result of being sent to the uniquely dangerous prison/mine. Other criminal Terileptils in the story without speaking roles did not have similar scars.
- People in Rubber Suits: The Terileptil Leader is notable in that it's the first rubber-suit monster to feature animatronics inside the head, which allowed its gills to move and eyes to blink.
- Starfish Aliens
- Shut Up, Kirk!: The Terileptil gets a pretty nice retort to the Doctor's request for diplomacy.
Trions (Fifth Doctor)
Trions are an alien species that the Fifth Doctor's companion Turlough belongs to.
- Deep Cover Agent: According to Turlough, the Trions had undercover agents on every civilized planet, including Earth.
- Human Alien: Trions look identical to humans and can survive in similar conditions. Since the nurse at Turlough's school had no problem when examining him, that would imply that Trions have similar, if not identical, internal structure to humans. Though based on Turlough's comments, he may be older than he looks, implying a different rate of ageing.
Sixth Doctor era debut
Vervoids (Sixth Doctor)
- From a Single Cell: The Doctor claims the Vervoids have the ability to reproduce from a single leaf.
- Plant Aliens: Technically they're manufactured by humans on a colony world, but the Vervoids see themselves as being different enough to animals that they indiscriminately slaughter them.
- Slave Race
- Starfish Alien
- Turned Against Their Masters: The Vervoids, though they never really accepted that whole thing about being slaves to begin with.
- Unfortunate Character Design: The first thing most viewers above a certain age will notice about the Vervoids is how much their heads look like a certain part of the female anatomy...
Seventh Doctor era debut
Haemovores (Seventh Doctor)
A race of vampiric, aquatic creatures that served Fenric they are implied to be the future descendants of humanity, mutated by toxic slime into bloodthirsty abominations. They are also partially psychic, and can be telepathically repelled if enough faith is exhibited in close proximity to them.
- Bad Future: Humanity will apparently evolve into Haemovores if Fenric succeeds in conquering Earth in the 1940s. It's not clear whether this potential future has been averted by the end of "The Curse of Fenric".
- Frozen Fashion Sense: The sequences where the Haemovores rise up to feast on the living display everything from Elizabethan doublets to eighteenth century seawool. Justified, as they've all been holed up since they were turned, and haven't exactly had a chance to nip down to the shops and pick up something more trendy.
- Holy Burns Evil: Haemovores can be repelled by faith itself. The Doctor repels them by repeating the names of all his companions, the fervently Communist Sorin repels them with a red star badge from his uniform, and Reverend Wainwright sadly fails to repel one using a bible, as the horrors of World War II destroyed his faith.
- Immune to Bullets: Bullets slow the Haemovores down, but can't kill them.
- Not Using the "Z" Word: The Doctor states that the Haemovores are not "vampires". Anyone to refer to them as such is immediately corrected.
- Our Vampires Are Different: Besides acting more like zombies than vampires, Haemovores can be blocked by a psychic barrier created by one's faith.
- Viral Transformation: How the Haemovores are created.
Ninth Doctor era debut
The Gelth (Ninth Doctor)
A once organic, now-intangible race of aliens who have been left as refugees as a result of the Time War. As a result of their wraithlike forms, they have to depend upon possessing and inhabiting decomposing human corpses in order to survive.
- False Innocence Trick: The Gelth claim to be refugees from the Great Time War who have lost their bodies and only want to use dead humans as Meat Suits. It turns out that there are many more of them than they claimed, and they want to take over all humanity, not just the dead ones. Granted, they're not actually lying the key here is that they just need dead bodies. A few billion. Which means a majority (if not all) of the human population of Earth at the time.
- Invading Refugees: The Gelth were fleeing the Time War.
- Nightmare Face: The Ambassador takes on a demonic visage when it reveals its true evil nature.
- Not Using the "Z" Word: The Gelth aren't called ghosts in the story, which is fair enough since they aren't actually ghosts, just gas creatures. They can also possess human bodies for a little zombie action.
- Puppeteer Parasite: They take over dead bodies.
- Red Eyes, Take Warning: You know the Gelth aren't what they claim when the one speaking through Gwyneth changes from a soothing uniform blue to having red eyes.
The Slitheen familynote (Ninth Doctor)
The first recurring aliens original to the revitalized Doctor Who franchise, the Slitheen are basically a family of Used Car Dealers and Con Men. IN SPACE! Their family hails from the planet of Raxacoricofallapatorius, where most of the family has been sentenced to death for being rather annoying and kinda evil. Unlike most alien baddies, they're a crime family, not an Always Chaotic Evil species the other Raxacoricofallapatorians are, according to the Doctor, rather peaceful. While they mainly only showed up during the Ninth Doctor's tenure (and an unidentified Raxacoricofallapatorian cameoing at the end of the Tenth's), the Slitheen also made it over to The Sarah Jane Adventures, where a rival family, the Blathereen, is often mentioned, and two Slitheen-Blathereen (orange-skinned Raxacoricofallapatorians) appear, along with a strange dark green-skinned Raxacoricofallapatorian. Perhaps the most unique feature about the Slitheen is their habit of skinning humans and using said skins as disguises.
- Affably Evil: They're only doing their business, after all, even if said business does involve destroying entire planets. Besides, hunting and killing are a trait of their species. They can't really help that, and they're pretty polite until you upset them.
- Always Chaotic Evil: Subverted. We're led to believe they're just another invading species, but they're actually a criminal syndicate. Raxacoricofallapatorians are rather peaceful.
- Becoming the Mask: Both Blon Fel-Fotch Passameer-Day Slitheen and her brother who impersonated Oliver Charles/Asquith appear to suffer from this. The former is horrified after she realised she's gone native after six months amongst the Welsh, while the latter regrets having to ditch his old skin suit, as he got to have "a wife, a mistress and a young farmer".
- Bizarre Alien Biology: They're made of calcium, able to smell fear and pheromones produced by humans, and can expel poison through their fingernails (via darts) or their breath. Due to their biochemistry, they also have a severe allergic reaction to vinegar (although it is implied that this only happens because the compression fields they use to hide in weaken their body's structure so much).
- Costumes Change Your Size: Justified with their technology, allowing them to fit inside of their tinier human disguises.
- Cruel and Unusual Death: The reason Slitheen don't go home. Their method of execution involves them being lowered into a vat of acid, which causes their innards to fall out, while the Slitheen's still alive. Then the acidy-slitheeny soup is drunk afterward.
- Egomaniac Hunter: The Slitheen family, at least, enjoy hunting and treat it like a ritual.
- Even Evil Has Loved Ones: They're a crime family that legitimately cares about each other after most of them are killed in their debut, Blon cries about her lost loved ones in a later episode.
- Evil Has a Bad Sense of Humor: They tend to act like evil, overgrown kids. Apart from the fart jokes, their idea of a fake alien is to take an ordinary pig, perform gruesome surgery on it and then stick it in a spaceship.
- Evil Plan: The family Slitheen seems to be rather good at vile schemes to enrich themselves. It's just that they don't count on the Doctor showing up, or Sarah Jane Smith.
- Exposed Extraterrestrials: When they're not in their human suits. Lampshaded with dialogue about it being traditional to hunt naked.
- Face Stealer: Along with the rest of your skin.
- The Family That Slays Together
- Fat Bastard: In their human disguises, as the eight-foot-tall Slitheen have to use the skins of overweight people for disguises.
- Gasshole: Not naturally, but squeezing into their human disguises requires a "gas exchange" that results in this. In their first appearance it is implied that this is an unintentional side-effect or the result of equipment malfunction, when the one impersonating Margaret Blaine says they've "got to fix the gas exchange", although this never comes up again.
- Hannibal Lecture: Margaret/Blon in "Boom Town" while trapped in the TARDIS, tries to guilt the heroes into releasing her. Jack says not to answer back, "... it's what she wants."
- Hunting the Most Dangerous Game: The Slitheen family, at least, really like hunting humans.
- Kill and Replace:The Doctor: You're pleading for mercy out of a dead woman's lips.
- Lady Looks Like a Dude: In one of their Big Finish appearances, a female Slitheen disguises herself in the skin of a male human.
- Only Known by Their Nickname: Members of their species are often referred to as "Slitheen", after the infamous crime family that hails from Raxacoricofallapatorius. The Doctor mentions that the other members of the species are peaceful and implies they're somewhat irritated by the Slitheen sullying their good name, which might explain why all the Slitheen family have been been sentenced to death on their homeworld.
- Overly Long Name: Raxacoricofallapatorius.
- Psychopathic Manchild: They often come off as sophomoric and immature given their amusement with the side effects of their Face Stealer technology.
- Rogues Gallery Transplant: After being introduced in the first season of the revival series, the Slitheen effectively migrated to The Sarah Jane Adventures, making more appearances there than in the show that birthed them.
- Toilet Humour: The best way to spot a disguised Slitheen? They fart. A lot.
- Weaksauce Weakness: Vinegar. Go figure.
Tenth Doctor era debut
Sycorax (Tenth and Eleventh Doctors)
The Sycorax were a superstitious race of warriors. They often wear skeletal masks, with equally skeletal faces underneath.
- The Cameo: In "The End of Time", "The Pandorica Opens", "The God Complex" and "The Magician's Apprentice".
- Blood Magic: They were able to control everyone on Earth with A positive blood after acquiring a sample.
- Duel to the Death: They believe in solving disputes by honourable combat, often to the death. The Sycorax Leader, however, violates this by attacking the Doctor even after he wins the fight and spares his life, leading to the Doctor triggering a nearby trap door that sends him plummeting to his death. Apparently the other Sycorax felt this either satisfied honour or didn't want to test the Doctor's patience, since they left shortly afterwards.
- HeelFace Door-Slam: After being beaten by the Doctor, the human race take the opportunity to fire upon them as they're peacefully leaving Earth, vaporising the entire asteroid.
- Historical In-Joke: The Doctor feeding Shakespeare his own lines. Specifically, it resolves the Brick Joke of the Sycorax set up in "The Christmas Invasion"; Sycorax is a witch mentioned in The Tempest, and where Shakespeare got the name is a bit of an academic mystery as far as anyone can find she's not a figure from mythology, and if it's a Meaningful Name it's far from obvious what the meaning is. "The Christmas Invasion" uses it as the name of an alien species, with no explanation/comment, and this episode has Shakespeare hear the Doctor talking about them and likes the sound of it.
- Insufficiently Advanced Alien: Not touched upon much, but they seem to believe in witchcraft and curses (it's how they describe the Doctor's regeneration). One can only guess what they think of Carrionites.
- Named After Their Planet: Doctor Who Files 4: The Sycorax calls their home planet "Sycorax".
- Planet Spaceship: The Sycorax come from an asteroid named Fire Trap, which was retrofitted into a starship when one fell upon its surface. They eventually built an entire Armada out of captured and colonised asteroids.
- Proud Warrior Race Guy: They believe in solving disputes with a Duel to the Death.
- Wizards from Outer Space: It's left vague whether their blood magic is actual magic or some kind of technology.
Catkind (Tenth, Eleventh and Twelfth Doctors)
A species of humanoid aliens which resemble felines, who hail from a planet called New Savannah. The Catkind first appear as an order of nuns called the Sisters of Plenitude in "New Earth". A subspecies called Leonians antagonises Ashildr and the Twelfth Doctor in "The Woman Who Lived".
- Cat Folk
- Cute Kitten: What the babies of this species resemble.
- Dominant Species Genes: A Catman and human female husband and wife produces a litter of kitten offspring.
- Female Feline, Male Mutt: Ultimately averted. Although the first Catkind we meet are unanimously female, this is because Rose and the Tenth Doctor have visited a convent. Later on, the Doctor meets male members of the same species.
- Saintly Church: The Sisterhood run a hospital founded by charity to heal the sick.
Ood (Tenth, Eleventh and Twelfth Doctors)
A race of telepathic humanoids native to the Ood Sphere (which is in the same region of space as the Sense Sphere). They were used as slaves during the Second Great and Bountiful Human Empire, until they were liberated by the Doctor, Donna and a spy for the Friends of the Ood.
- Bizarre Alien Biology: They're born with secondary brains in their hands. The company that enslaved them cuts them off to make them docile.
- The Cameo: An Ood is briefly seen as a resident of the trap street in "Face the Raven", repairing a Cyberman.
- Cthulhumanoid: A mass of tentacle like appendages hanging from where mouths should be.
- Dark Is Not Evil: Zigzagged. Despite their monstrous appearance, the Ood are peaceful and gentle. However, they wind up taking an antagonistic role in almost every appearance. A large part of the problem is that their hive mind leaves them open to Demonic Possession.
- Happiness in Slavery: Via lobotomy.
- Hive Mind: Governed by a large living brain situated on their planet called the "Ood Brain", without it the Ood would die.
- Perfect Pacifist People: They are naturally a peaceful race, which is why the humans chose to turn them into a Slave Race.
- Red Eyes, Take Warning: When they were controlled by the Beast. And later again when the Ood Brain managed to reach out and make the Ood take revenge against their human captors.
- Russell T Davies has acknowledged the Sensorites as an influence on the basic concept of the Ood in "The Impossible Planet" and "The Satan Pit". Computer read-outs (and a mention by Davies in an episode commentary) revealed that the Ood Sphere and Sense Sphere are part of the same star system.
- Also Mind Flayers aside from their appearance, the flayers eat brains (the Ood vomit one of theirs forward upon maturing), and both serve an Elder Brain.
- Slave Race
- Weak-Willed: In addition to their status as a Slave Race, the Ood seem to be particularly susceptible to possession by outside entities.
- Explained by Donna Noble and confirmed by the Doctor that it's due to the fact that they're born with their brains in their hands. With such a glaring evolutionary weakness, they have no choice but to trust everything simply as a survival mechanism.
- We Will Use Manual Labor in the Future
Judoon (Tenth, Eleventh, Twelfth and Thirteenth Doctors)
The law enforcement arm of the Shadow Proclamation, Judoons look like bipedal rhinos in Badass Biker gear. They are extremely fond of rules and regulations, as seen in The Sarah Jane Adventures, and a bit thick.
- Badass Biker: Just the outfits, not the rebellion.
- Berserk Button: Damaging a Judoon's nose-horn is the single most insulting thing you can do to them.
- The Bus Came Back: After their debut in "Smith and Jones", it would take 13 years for their next major appearance on Doctor Who proper in "Fugitive of the Judoon".
- By-the-Book Cop: Played with; although the Judoon strictly obey the letter of the law, their "book" allows for a lot of Cowboy Cop or even Knight Templar behavior on their part.
- The Cameo: All of their appearances on Doctor Who between "Smith and Jones" and "Fugitive of the Judoon", with their most prominent appearances otherwise being in "The Stolen Earth" and the prequel to "A Good Man Goes to War".
- Ashildr's bodyguards in "Face the Raven" are revealed to be Judoon when the misdirection circuit is temporarily disrupted.
- Cowboy Cop: The Judoon are known to bend the rules to help find their target. They can transport a whole hospital offworld and use unsanctioned tech and weaponry if it gets the job done.
- Disproportionate Retribution: Strike a Judoon? Sentence: execution, by means of disintegration. Interfere with its interplanetary police work? Expect the same. Live on the same planet where a mass-murdering criminal has taken refuge? Your whole blasted planet gets destroyed if the Judoon haven't been instructed to recognize you as a species worth protecting.
- The Dragon:
- As a whole, for the Shadow Proclamation.
- The Time Lords hired them to find a fugitive.
- Dumb Muscle: As the Tenth Doctor puts it, they're thick. The ones he encounters nab an entire hospital to find one patient, then wipe the hospital records, requiring them to go on an extensive patient-by-patient search which allows their target to hide. And when they find an alien, they immediately shoot to kill, not bothering to check said alien is the one they're looking for.
- Guttural Growler: All of them, gals included, speak in deep gutteral growls.
- Hell-Bent for Leather
- I Gave My Word: Once a Judoon platoon takes a contract, they will finish it. The Thirteenth Doctor learns this the hard way.
- Inspector Javert
- Judge, Jury, and Executioner: "Justice is swift."
- Law Enforcement, Inc.: Their hat.
- Lawful Stupid: The Judoon have an almost one-track sense of justice. They will execute anything and everything for the slightest offense, no matter if they're lashing out because they feel cornered, an alien criminal, or just in the way. But if you get on their good side, they might simply ground you from space travel.
- Perpetual Frowner: Their faces seem set in this expression.
- Pet the Dog: They do offer compensation to beings they have inadvertently hurt.
- Rhino Rampage: Alien rhinos, and are naturally depicted as burly and aggressive.
- Space Police: Or police-for-hire, as the Doctor puts it.
- Trigger Happy: Especially in The Sarah Jane Adventures.
Toclafane (Tenth Doctor)
In the year 100 trillion, when the universe is finally ending, the Master manages to trick the last vestiges of humanity into escaping to Utopia, where they are forcibly turned into the Toclafane. Named after creatures from a Gallifreyan fairy tale, the humans of the far future have been twisted into psychopathic cyborgs with the minds of children; integrated into spherical, mechanical shells. The Master used them as muscle when staging his invasion of Earth during "The Year That Never Was".
- Children Are Innocent: Averted. The Toclafane display childish personalities and speech patterns, but they are psychotic, sadistic and callous, even when fighting their own ancestors.
- Cybernetics Eat Your Soul: They mutilated themselves into their current state and are willing to kill off their ancestors.
- Cyborg: They are human heads encased inside robotic spheres.
- For the Evulz:Martha: But why? Why come all this way just to cause all this death and destruction?
Toclafane: Because it's FUN!
- Grandfather Paradox: The Master's Paradox Machine allows the Toclafane to freely murder their own ancestors without worrying about this. When it's destroyed, the timeline corrects itself.
- Human All Along: The Toclafane turn out to be the humans from the far future from "Utopia".
- Humans Are the Real Monsters: The Toclafane are the future of humanity, who turned themselves into cyborg Psychopathic Manchildren in a desperate attempt to survive the collapse of reality. Why are they slaughtering their own species? Simply because it's fun.
- Madness Mantra:Toclafane: We shall fly and blaze and slice! We shall fly and blaze and slice!
- Natural End of Time: They were originally the last of humanity at the end of the universe, who sought out Utopia to avert their destruction. Unfortunately it was a wasteland and they devolved into the Toclafane to survive. And when that failed, the Master offered them to invade the 21st century and have another 100 trillion years to rule.
- Psychopathic Manchild: An entire race of them, no less.
- Same Story, Different Names: The Toclafane's origin story mirrors that of the classic Cybermen in "The Tenth Planet". In that episode, the Earth's lost "sister planet" of Mondas returns along with humanity's evolved cousins, who turn out to be metallic fossils of their former selves. Those events prove too much for the First Doctor, who dies of exhaustion. Ten fares a little better here, though he still ages a lot, and his faith in humanity is once again shaken. The Twelfth Doctor, while not directly referencing them, discusses that humanity eventually cybernetically upgrading themselves in order to survive in extreme circumstances is an inevitability, the various origins of the Cybermen simply a case of parallel evolution. In that respect, the Toclafane effectively are a very twisted and insane version of the Cybermen. The key difference is that Cybermen eliminate their emotions while the Toclafane openly take sadistic pleasure in killing.
- Transhuman: The last generation of humanity transformed into cybernetic spheres.
Adipose (Tenth Doctor)
A friendly race of marshmallow-like blob creatures that appeared primarily in "Partners in Crime", created from living fat.
- Baby Talk: A justified example, as in their debut they were babies.
- Black Bead Eyes: Their eyes lack any detail, being simple black circles.
- Blob Monster: In the words of Matron Cofelia, "the fat just 'walks away'."
- Breakout Character: Merchandise-wise; the species has only had a major role in "Partners in Crime" and minor roles in a few other episodes, but (mainly thanks to their cute and huggable design) they're still a major part of the merchandise to this day, being sold mainly as plush toys.
- Children Are Innocent: Pointed out by the Doctor, to Donna. Being newborns, they're not responsible for the methods Matron Cofelia used to bring them into the world.
- Human Resources: A special "weight-loss" pill you took would convert your fat into Adipose. Unlike most examples of this trope in general, this actually leaves you better off since you've lost weight and they harmlessly leave when you're asleep with you none the wiser. Just make sure that they don't begin emergency parthenogenesis...
- Ridiculously Cute Critter: Baby Adipose look like plush toys.
- Powered by a Forsaken Child: When they are created via emergency parthenogenesis, the person they come from dissolves into Adipose and dies. This is not their fault, but rather the fault of their "foster mother".
- Mascot Mook: The Adipose are the mascot of the show's official Tumblr blog, mostly due to how incredibly cute and huggable they are.
- The Worm That Walks:
- In "Partners in Crime", they were born when the fat of a taker of an Adipose pill dissolved into a swarm of them.
- Used in a darker vein in "Turn Left", when in the altered timeline, millions of Americans were dissolved to create them.
Pyroviles (Tenth Doctor)
Magma-monsters who hail from the stolen planet of Pyrovillia, they attempt to turn humanity into Pyroviles by harnessing the volcanic eruption of Mount Vesuvius.
- Evil Is Burning Hot
- Living Lava: Creatures of magma and molten rock that vaguely resemble Roman centurions.
- Made of Incendium
- Psychic Powers: They're capable of activating them in the Sibylline priestesses, and all the other seers in Pompeii.
- Taken for Granite: A side-effect of the Pyroviles taking over their human hosts is stone limbs.
- Take Over the World: The Pyroviles plan to emulate Rome by taking over the entire known world and likely everything else on the planet.
- Silicon-Based Life: They look like giant rock golems.
Hath (Tenth and Twelfth Doctors)
Bizarre looking, man sized fish people. First encountered as a clone army by the Tenth Doctor.
- Androcles' Lion: The Hath trust Martha because she helps one of them with a dislocated shoulder.
- Clone Army: When first encountered.
- Ditto Aliens: All look pretty much alike.
- Fish People: Rather large fish people at that.
- Future Imperfect: The human/Hath creation myth is actually their arrival by spaceflight on this planet. It might have to do with the "countless generations", even if the terraforming ship only landed there last week.
- Mobile Fishbowl: The Hath breathe a nutrient liquid, and have to wear a mask containing a flask of it while in Earthlike atmospheres.
- The Unintelligible: Communicate by bubbling the odd containers of green liquid in their mouths.
Vashta Nerada (Tenth Doctor)
- "These are our forests. They are our meat."
Also known as "The Shadows that Melt the Flesh", the Vashta Nerada are tiny scavengers that hide in the shadows, any shadows, before consuming their prey. They are found on every world, including Earth.
- Broken Record: Someone consumed by a Vashta Nerada will have their neural chip "ghosting" and repeating the same phrase on a loop.Proper Dave: Hey, who turned out the lights? Hey, who turned out the lights?
- The Croc Is Ticking: You can tell that a swarm of Vashta Nerada has eaten someone when the microphone starts acting like a Broken Record and repeats the same phrase over and over.
- Darkness = Death: If you enter a shadow that the Vashta Nerada occupy, you will be devoured.
- Dark Is Evil: Living Shadows that devour humans and strip them to the bone.
- It Can Think: They are very quick learners. When one of the group is eaten, they hijack the suit and project more shadows around them, turning it into an "Instant Death" Radius, in order to increase their hunting capabilities. Then they start to tweak the suit's data ghost to speak and learn how to do so fluently within the next few hours at most.
- Know When to Fold 'Em: Despite having no way of actually fighting them, the Doctor intimidates the swarm into withdrawing just by daring them to look up his name.
- Living Shadow: A swarm of Vashta Nerada looks like a dark shadow moving across the ground. They can even form the shape of a humanoid to animate spacesuits.
- Names to Run Away from Really Fast: "The Shadows that Melt the Flesh" doesn't sound very appealing, does it?
- Non-Malicious Monster: Played With; Normal Vashta Nerada are benign and mostly live off of roadkill and carrion. The ones in the library are unusually aggressive.
- Primal Fear: They are implied to be the reason that many species have a natural fear of the dark.
- Stripped to the Bone: When they devour humans and a chicken leg, all they leave are bare bones.
- The Swarm: They're thousands of microscopic carnivores working in unison.
- The Worm That Walks: The swarm invaded a spacesuit and devoured the original occupant. They started piloting the suit to capture other prey. They haven't perfected it yet, they are quite slow and stiff.
- Zombie Gait: It's not like spacesuits are designed to be piloted by swarms of thousands of miniscule creatures that ate the previous occupant.
The Flood (Tenth Doctor)
Water-dwelling microbes capable of possessing other species. The Ice Warriors froze the Flood into a glacier underneath a crater on Mars, but thousands of years later, it found its way into a human space base built inside the crater after the failure of a water filter. It wanted to find its way to Earth after finding out just how much more water there is there, compared to Mars.
- Demonic Possession: Contact with Flood-infected water turns people into extensions of it, killing their original personality.
- The Juggernaut: The characters in "The Waters of Mars" have no way to slow down or stop the Flood after it's loosed other than blowing up the entirety of Bowie Base One. As the Doctor says, "water is patient".
- Murder Water: Contact with just one drop of Flood-infected water is enough to cause possession. Infected can also create water jets strong enough to cut through steel.
- Nightmare Face: Humans infected by the Flood develop white irises and cracked skin around their mouths, with black teeth and water constantly seeping out of the mouth.
- The Virus: The Flood's primary objective is to infect as many people as possible, and to get into as much water as possible, which is why Earth appeals to it so much.
Eleventh Doctor era debut
The Atraxi (Eleventh Doctor)
A cosmic police force of flying crystalline aliens, who are also the wardens of an inter-dimensional prison. They track down escaped convicts and terminate them with extreme prejudice... unfortunately, "extreme prejudice" means that they're willing to destroy an entire planet to eliminate their quarry.
- Blue-and-Orange Morality: To an extent, considering their willingness to roast the planet.
- Canon Immigrant: The planet Atraxi 3 is first mentioned in the Eighth Doctor Adventures novel Vampire Science.
- Do Not Adjust Your Set: The Atraxi are capable of hijacking every transmission on every TV and radio channel on Earth in their search for the escaped Prisoner Zero.
- Faceless Eye: Giant flying eyeballs surrounded by a crystal snowflake.
- Giant Eye of Doom: They're nothing but the eye.
- Kill It with Fire: How the Atraxi intend to deal with Prisoner Zero and the human "residence".
- Know When to Fold 'Em: Defied by some skinny dude in the bow tie, they research Earth's history and discover exactly who they're threatening. After that realisation, they quickly and wisely decide to get the hell out of dodge and never return.
- Oculothorax: The Atraxi are a Giant Eye of Doom that can fly through outer space though that part is implied to be a starship, or fleet thereof.
- Oh, Crap!: After they realise that not only is Earth very familiar with alien visitors, there's a reason it's still intact... and that reason is standing right in front of them.The Doctor: Hello. I'm the Doctor. Basically... run.
- Space Police: Even more alien and more callous than the Judoon, after a fashion. They're prepared to torch an entire planet just to make sure Prisoner Zero doesn't escape. On the other hand, they're not as hair-trigger about "crimes" as the Judoon are, so much less likely to kill or threaten random civilians.
- Starfish Aliens: They put the "alien" in "alien police" with their big eyeballs and crystalline web ships.
Gangers (Eleventh Doctor)
- "It's us or them."
The Gangers were a clone race created by humans from an artificially created organic substance called the Flesh.
Gangers were primarily created so workers who had extremely dangerous jobs could work without the fear of bodily harm or death. The Ganger is just an avatar, a robot-like being that is mentally controlled by the original. If a Ganger is destroyed or gets mortally wounded, another Ganger is created for the consciousness to inhabit. Well, that's how it's supposed to work, at least. In the story they initially appear in, the Gangers are cut off from the originals, leading to them developing minds of their own (and retaining all of the original's memories), essentially turning them from avatars to clones. They immediately understand what has happened, and plot to escape the base, not particularly caring if the originals get killed in the process. (After all, they aren't actually different. At all.)
- And I Must Scream: The partially melted down Gangers; rotting but fully alive and conscious.
- Body Horror: The rotting Gangers partially melted but still conscious. There are eyes in one of the walls, made of more living Flesh.
- Chekhov's Gun: In "A Good Man Goes to War", a Ganger is used as a duplicate for Melody.
- Clones Are People, Too: Heavily explored and established, especially with the Gangers of Jennifer and Jimmy.
- Cloning Blues: After being cut off from the people they're based on, they have a violent identity crisis because their memories say they are real but their circumstance says they're not.
- Continuity Nod: In "The Almost People", one decommisioned Ganger resembles the villainous Cassandra from "The End of the World" and "New Earth". The Gangers also seem to be "force-grown clones", like Chip, Cassandra's servant.
- Deadly Euphemism: Gangers, being considered implements, are not killed but "decommissioned". Justified in that originally they were avatars of people, not sentient beings in and of themselves.
- Finishing Each Other's Sentences: This happens with the Doctor and his Ganger; same wavelength!
- Glamour Failure: The Gangers occasionally shift back to their gooey, half-formed selves for a brief moment.
- Go Mad from the Revelation: Ganger!Jennifer completely loses it thanks to all her memories of being "decommissioned".
- Hive Mind: The two Doctors manage to act as if they were still occupying the same skull. Which, in a way, they are. Both being essentially exactly the same person, it would make sense that they would know exactly what the other was thinking. The fact that Time Lords are telepathic couldn't have hurt, either.
- In-Series Nickname: The TARDIS team seem to have dubbed them "Flesh Avatars".
- Meaningful Name: "Ganger" comes from both "doppelgänger" (a duplicate of a person) and "ganger" (a menial labourer assigned to a large work gang, i.e. on old-fashioned railroads).
- Nightmare Face: An incomplete Ganger has a gooey white face.
- Replacement Goldfish: Two of the original humans are killed and their Gangers resume their lives for them.
- Rubber Man: Ganger!Jennifer is able to stretch her hand all the way from inside of a toilet stall to punch the mirror on the other side of the room.
- Tomato in the Mirror: The Gangers of the factory staff, after the solar tsunami that made them sentient, don't immediately realize that they're not the originals, and are somewhat unnerved when they learn this, as demonstrated with Cleaves.
- What Measure Is a Non-Human?: The Gangers are designed to be expendable their purpose is to mine the acid, a horribly dangerous job, without putting humans at risk. Naturally, they aren't happy about this.
Tivolians (Eleventh and Twelfth Doctors)
The Tivolians are a race of rodent-like humanoids from the planet Tivoli. Their homeworld is the most invaded planet in the galaxy, to the point where the Tivolians now actually enjoy being conquered and oppressed.
- Les Collaborateurs: They willingly comply with any conquerers. It's implied to be a species-wide survival strategy: if everyone knows they can be effortlessly conquered, no one ever tries to exterminate them.
- Dirty Coward: They straddle the line between these this and Lovable Coward. In "The God Complex", Gibbis' cowardice is often the source of humour, but his lack of bravery also gets someone killed and the Doctor is very unhappy with Gibbis after that.
- Getting Crap Past the Radar: In "Before the Flood", Prentis' love of being oppressed seems sexual in nature. The Doctor is not amused.
- Jerkass: Gibbis takes enjoyment in discovering Amy's fear, as it might be somewhere inside the hotel.
- Planet of Hats: An extreme example even for Doctor Who. An entire race of people who love being oppressed by invaders.
- The Quisling: An entire planet who welcome any and all alien invaders. Their planetary anthem is "Glory to <Insert Name Here>".
- Rubber-Forehead Aliens: Tivolians look like humans with rodent-like features.
- Stockholm Syndrome: One interpretation for why the Tivolians enjoy being oppressed.
- You Dirty Rat!: The species has rodent-like features. They are also shameless cowards who'd throw others under the bus for their own safety.
Whisper Men (Eleventh Doctor)
Mysterious beings who work for the Great Intelligence. They appear to be extensions or manifestations of the Great Intelligence himself, as if he destroys his current form, he can then take the body of one of his Whisper Men.
- Badass in a Nice Suit: Dress in Victorian era garb.
- The Blank: Lack facial features except for one large gaping mouth.
- Foil: To the Silence; while both wish to destroy the Doctor, they do so in completely opposite ways. The Silence wish for "Silence to fall" and their ultimate goal is to prevent the Doctor from saying his name. The Whisper Men want the Doctor to say his name aloud so the Great Intelligence can enter the Doctor's tomb. This also extends to their physical appearance, while both have Nightmare Faces and wear suits, there is one very important contrast. The Silence have large eyes and no mouth, the Whisper Men have a big gaping mouth and no eyes.
- Intangible Man: When Strax tries to strike them, his weapon passes right through. They can also phase their hands through their enemies' hearts.
- Mooks: To the Great Intelligence.
- Nightmare Face: Faceless horrors, save for one large snarling mouth.
- Rhymes on a Dime: Always speak in rhymes.
Twelfth Doctor era debut
Kantrofarri, aka "Dream Crabs" (Twelfth Doctor)
The Kantrofarri, colloquially known as the Dream Crabs, are telepathic parasites which feed on humanoid brain matter, and have the appearance of giant misshapen hands. They keep victims in a placid dream like state as they dissolve their brains.
- Big Creepy-Crawlies: They're colloquially called "crabs", and have spider-like movement, but actually resemble giant, misshapen hands.
- Dream Within a Dream: They create layer upon layer of dreams, so that the victim can never discern dream from reality.
- Enemy Within: Sort of. Once they've latched onto your face, your only means of survival is realizing it's a dream and breaking out from within your mind.
- Expy: Of the Facehuggers.
- Face Hugger: They latch on to their victims' faces so they can eat their brains.
- No Body Left Behind: They crumble to dust once they die. The Doctor explains that this is a "carnivore's hazard, food has teeth too".
- Schrödinger's Butterfly: The Doctor states that there is no one who can ever be sure whether or not they are dreaming or not, and the Dream Crabs who create a Dream Within a Dream certainly make this much harder.
- Starfish Aliens: Creatures which look like misshapen hands, with no eyes, ears, nose, or mouth and rely on telepathy to detect the image within other nearby organisms.
- Sweeping Ashes: The first time they die and crumble to dust, Shawna comes in and sweeps them up.
- Telepathy: The only way they can sense the world around them, literally homing in on the image of themselves in their prey's mind.
Handmines (Twelfth Doctor)
A bionic defence system employed by the Thals against the Kaleds in the Thousand Year War for Skaro, these sinister hands burrow under the ground and are triggered by noise or footsteps. They then emerge and grab their victims by the ankles, pulling them underground. As a child, Davros was caught in a Handmine field before being rescued by the Twelfth Doctor.
- Eyes Do Not Belong There: The hand mines have eyes on their palms.
- Helping Hands: They don't seem to exist from the elbow down.
- Living Weapon
- Mythology Gag: The eye on the palm of the hand may be the same kind of cybernetic eye which Davros later has embedded in his own forehead.
- Quicksand Sucks: When the handmines grab people, they drag them beneath the dirt.
- Schizo Tech: As is quite common in the Thal-Kaled war. The Handmines are highly advanced, while the Thals also have biplanes mounted with laser weaponry.
Shoal of the Winter Harmony (Twelfth Doctor)
- Ascended Extra: They go from being relatively minor villains in "The Husbands of River Song" to the Big Bad of "The Return of Doctor Mysterio".
- Bald of Evil: Scratch, their spokesman in "The Husbands of River Song".
- Big Bad: They serves as the main threat of the 2016 Christmas special.
- Brain in a Jar: They literally appear as brains in jars before they are transplanted to a new host.
- Brain Theft: They infiltrate planets by transplanting their brains into that of civilians.
- Evil Plan: Take Over the World. Of Course.
- Expy: They are not unlike the Slitheen as aliens who pretend to be humans by wearing the skins of their victims.
- Good Scars, Evil Scars: They can be spotted as having a telltale diagonal scar running across their faces, which can actually split open.
- Grand Theft Me: The modus operandi of this alien menace, who swap themselves into human hosts while removing their brains.
- Hyperspace Mallet: Harmony Shoal members are able to store things in their heads. Literally. They just split open their head and pull the item out.
- Kill and Replace: They surgically remove the brains of their victims, before one of their species is put inside the body as a vessel.
- Manipulative Bastard: Their Evil Plan is so brilliant that even the Doctor is impressed, before complaining how his side never comes up with ideas like this.
- Red Right Hand: Harmony Shoal Members can be distinguished by a telltale seam running diagonally down the side of their face, some of which may also have a tendency to exude blue liquid out of the openings in their faces.
The Pilot (Twelfth Doctor)
A mysterious liquid entity formed out of spaceship oil that desires to consume a "Pilot" so that it may be controlled and return to the stars where it belongs. It was attracted by Heather's star-shaped defect and desire to "escape" and fused with her. From there it pursued Heather's crush, Bill Potts, across space and time, driven by her promise not to leave without her.
- Chekhov's Gunman: While she was a Monster of the Week, Pilot!Heather returns just in time save Bill from total Cyberman conversion and gives her the power to become a Pilot in the season 10 finale.
- Elemental Shapeshifter: Can transform into a pure liquid form. Even in human form, it is constantly dripping wet.
- Implacable Man: Absolutely nothing can get in between the Pilot and its assigned passenger. Not the TARDIS. Not a Dalek. Not even the Time Vortex itself.
- Inexplicably Awesome: Why a puddle of alien oil merged with an ordinary human woman equals a Physical God, we may never know.
- Intangibility: As a liquid entity, anything thrown at it just passes straight through harmlessly.
- Offscreen Teleportation: After consuming Heather, it gains the ability to form itself out of humid surfaces such as puddles or the steam in mirrors, allowing it to follow the TARDIS around.
- The Power of Love: Bill and Heather's love was strong. So strong that the Pilot kept something of hers, her own life water, as a way to hold onto Bill so that she could return to her one day.
- Reality Warper:
- Alongside its teleportation abilities, the Pilot is capable of time travel, shapeshifting, instant regeneration and mimicry.
- As of its return in "The Doctor Falls", Pilot!Heather seems to have mastered atomic reconstruction, making it a literal example of this trope.
- Riddle for the Ages: It is never revealed where the spaceship that left behind the oil that became the Pilot came from.
- Stalker with a Crush: After consuming Heather, the Pilot creature begins pursuing the TARDIS to transform Bill Potts into a "Passenger"; these impulses are caused by Heather's feelings for Bill.
- Stringy-Haired Ghost Girl: After possessing Heather's form, it invokes the imagery with its pale skin, association with water and the fact that it relentlessly haunts its victims.
- Super-Persistent Predator: It can and will follow its target anywhere and anywhen.
- Swiss Army Tears:
- The tears planted on Bill by Pilot!Heather are used to locate and rescue her after her conversion in the Mondasian Ship.
- After leaving the Doctor's corpse in the TARDIS, Passenger!Bill leaves a tear on his forehead, allowing his regeneration to resume.
The Dryads (Twelfth Doctor)
A species of small, possibly alien insects capable of merging and transforming people into wood, a group of them inhabit the Landlord's house, obeying his commands through high-pitched sounds.
- Big Creepy-Crawlies: Each dryad seems to be about the size of a fist.
- Insect Queen: The Landlord seems to be the one ordering the Dryads and giving them sustenance. Averted when it turns out Eliza, the Landlord's mother, is the one with an actual psychic connection to the lice, hinting at a possible Hive Mind.
- Plant Person: The Landlord's mother, Eliza, was transformed into living wood by the Dryads many years before the events of the story, recieving sustenance from the people fed to the dryads by the Landlord.
The Monks (Twelfth Doctor)
An unnamed race of beings that appear to the human race as creatures resembling mummified corpses in red monk robes. They possess technology that allows them to create highly elaborate illusions and simulations.
- Arc Villain: Of a trilogy consisting of "Extremis", "The Pyramid at the End of the World" and "The Lie of the Land".
- Bond Villain Stupidity: They fall into this big time in "The Lie of the Land". They do very little to actually stop the Doctor and his companions foiling them.
- The Chessmaster: They run simulations of a race's entire history to find the perfect moment to manipulate that race into asking to be conquered. They also have the common chessmaster weakness of complacency; because their plans are normally foolproof, they're very badly prepared to react to said plans hitting a snag.
- Deal with the Devil: They offer to save humanity from an inescapable doomsday scenario which will cause the extinction of all life on Earth, in exchange for humanity submitting before them and permitting them to rule planet Earth.
- Foil: To the Silence; while they both alter memories, they do it for the opposite purpose. The Silence have been ruling from the shadow and convincing people that they don't exist, the Monks convince people they were always there to get them to accept their rule.
- Internal Retcon: They maintain their rule with a signal that makes everyone believe they've always been in charge.
- Laser-Guided Amnesia: They remove all trace of themselves from Earth after they are defeated.
- Oddly Small Organization: They go to great lengths to establish a worldwide presence, but there are at most a dozen of them.
- Pragmatic Villainy: Even though they are powerful enough that they could conceivably subjugate Earth through force and rule through fear, they consider fear an inefficient means of control and insist on gaining humanity's consent to be ruled (via a Deal with the Devil) before they take over the planet.
- Prescience by Analysis: Given enough time and data to work with, their computers can predict a planet's future down to a remarkably fine level of detail.
- The Power of Love: In order to conquer somewhere, they need to have consent from an individual acting out of pure love. This lets them establish a link to brainwash the rest of the planet.
- Reality Warper: Can perform such feats as teleporting a submarine to a desert and restoring someone's sight.
- Suspiciously Similar Substitute:
- What Measure Is a Human?: A rather dark variant. The Monks are assuming the form of what they see humans as, not A Form You Are Comfortable With. To the Monks, humans are literally rotting corpses due to their brief lifespans.
The Eaters of Light (Twelfth Doctor)
A race of quadrupedal beings from another dimension who enter our universe through a tear in space located in ancient Scotland, if let loose they are capable of consuming entire stars to satiate their hunger.
- Energy Absorption: The beasts are capable of feeding on all forms of light, even that located inside living beings, killing them instantly.
- Year Outside, Hour Inside: Time runs slower inside their dimension compared to Earth, causing days to pass when one spends only seconds inside, This proves instrumental to their defeat, as a group of Picts and Roman soldiers blocking the gateway for a few days at max is enough to keep them at bay until the portal collapses naturally.
The Testimony Foundation (First and Twelfth Doctors)
Glass avatars from the Testimony Foundation, they travel through time snatching up people who are close to death, duplicate their memories into digital format, and then put them back to their human bodies at the moment of their death with no pain or strife, or any memory of the Testimony process. The memories and personality then could be uploaded into the avatar, and live on after their demise.
- Artificial Afterlife: What they benevolently aim to provide.
- Brain Uploading: Their whole M.O. is to collect memories of the dead as a living memorial of sorts.
- Cloning Blues: Averted. None of the deceased people within Testimony's database seem particularly bothered by the fact that they're copies of their "real" selves.
- Fantastic Racism: A strange case considering that Testimony was created in the far future where humanity regularly interacts with other species, but Testimony exclusively targets deceased humans for some reason. Nardole is the exception only because he guilted them into taking him, but that only proves that alien species are compatible with the system's matrix, thereby removing that as a valid excuse.
- Final Boss: To both the First (retroactively) and Twelfth Doctors, but as it turns out, Testimony were Good All Along.
- Good Counterpart: To the Nethersphere, another Artificial Afterlife created by Missy for decidedly more sinister purposes that appeared as the Arc Villain of the Twelfth Doctor's first series, thereby giving his entire tenure a sense of thematic closure. Both Testimony and the Nethersphere even use physical avatars to host each dead consciousness.
- Living Forever Is Awesome: Every dead person downloaded into Testimony that we see appears to be perfectly content with eternal life in the foundation's database.
- No Antagonist: The Glass People do plan something, but they aren't malevolent.
- Poor Communication Kills: The whole episode could have been resolved in 10 minutes tops had the Glass People explained what they were doing right up front and why.
- Downplayed, as no one is really harmed as a result of this miscommunication and the only real negative consequence is the waste of some time. Testimony also wanted to fully "get to know" the Doctor's character, which they deem to be good after observing his actions in the episode.
- Silicon-Based Life: Glass People are humanoid but completely see-through when they aren't serving as avatars of the dearly departed, like living glass sculptures.
Thirteenth Doctor era debut
Stenza (Thirteenth Doctor)
A Proud Warrior Race from a very cold planet who hold ritual hunts on other worlds. They are also conquerors who have wiped out most life on one planet, and are "cleansing" another... and that's just what we know about so far. They have apparently conquered parts of twelve galaxies.
- Arc Villain: Subverted, it seems like they were being set up as the Doctor's primary adversary for Series 11, but in the end Tzim-Sha is the only Stenza she faces.
- Battle Trophy: Stenza warrior Tzim-Sha takes one tooth from each of his victims, implanting them in his face.
- Enclosed Extraterrestrials: They wear armour on Earth because it's much warmer than their homeworld, and presumably it helps them deal with the different climate. However, they can expose their hands and faces briefly with no ill effects.
- Hive Mind: In "The Battle of Ranskoor Av Kolos", Tim Shaw reveals that the Stenza have one, allowing him to recreate their technology while trapped on Ranskoor Av Kolos.
- Hunting the Most Dangerous Game: Their ritual hunts involve sending a warrior to another planet, such as Earth, to hunt one randomly designated inhabitant. The trophies are taken back to the Stenza homeworld and kept in a state between life and death.
- Karma Houdini: Whatever happened to Tzim-Sha aside, the Stenza don't get punished for their cruelty and the Doctor, for all her disgust of their barbaric customs, doesn't bother to hunt them out and put an end to them.
- Kill It with Ice: Their body temperature is so low they can kill humans via lethal freezer burns on skin contact.
- Must Be Invited: Their hunts must be permitted by a resident of the planet it's taking place on before a pod can be teleported there. However, this permission takes the form of a glowing button with no instructions, so it's perfect Schmuck Bait for a person to ignorantly press without knowing what they're agreeing to.
- No-Gear Level: Their ritual hunts are supposed to be completed without any weapons.
- Proud Warrior Race:
Pting (Thirteenth Doctor)
A species of little space gremlins, capable of devouring any form of inorganic matter.
- Cute Monster: They're surprisingly adorable-looking for how dangerous they are.
- Extreme Omnivore: And we mean any form of non-organic matter, from screws to particle accelerators.
- The Juggernaut: They can eat through anything that would restrain them or block their path, and cannot be harmed by any known weapon. The spaceship computer's entry on them simply advises to stay far away from them.
- Nigh-Invulnerability: They're immune to most conventional weaponry. Even the one weapon that does affect the one seen merely stuns it for a few seconds.
- Non-Malicious Monster: They only attack starships because they're hungry and sees them as food. They don't even appear to be sentient.
- Pint-Sized Powerhouse: They're only about the size of a baby, but are extremely fast and dangerous. General Cicero mentions she previously encountered a Pting that devastated an entire fleet.
- Poisonous Person: Their skin secretes a toxin lethal to all other lifeforms.
Thijarians (Thirteenth Doctor)
An ancient race of assassins, there are only two left, as their planet was destroyed. Now, they bear witness so that others won't have to die alone.
- The Atoner: The Thijarians were once feared assassins, until their world was destroyed. Now, they bear witness for the dying.
- Dark Is Not Evil: They didn't bother to change their black-and-red outfits and Spikes of Villainy after turning over a new leaf.
- The Dreaded: They gained a reputation as the universe's finest assassins. When the Doctor realizes who they are, she's terrified.
- Due to the Dead: They have taken up a mission of doing this by bearing witness to the deaths of those who would have otherwise died alone and unmourned.
- Extra Eyes: They have a lot of eyes on their faces.
Morax (Thirteenth Doctor)
A race of sentient mud that was imprisoned under a tree in Bilehurst Cragg, Lancashire. Their goal is to escape their imprisonment and take over the planet, by taking over the bodies of people they come in contact with.
- Demonic Possession: This is what their preferred method of conquest looks like to the people of 16th century England. Doesn't help that they can take over dead bodies in addition to living ones.
- Our Zombies Are Different: Of the Possessing a Dead Body variety.
- Puppeteer Parasite: What they really are is mud that fills into a host body.
- Sealed Evil in a Can: They've been trapped inside a prison made to look like a tree on a hill in Lancashire.
Ux (Thirteenth Doctor)
A race of religious, nigh-immortal Reality Warpers only found on three planets in the universe, with only two existing at any one time.
- Facial Markings: They have raised, scar-like spiral markings on their cheeks.
- Obliviously Evil: The coincidental arrival of ailing Stenza warrior Tim Shaw on their planet led to the older Ux, Andinio, assuming that he was their Creator and doing his bidding, which eventually included stealing multiple planets. Due to the Ux being rather naïve, it wasn't until the Doctor arrived and proved that she knew the "Creator" that Andinio was shaken out of this belief. The younger Ux, Delph, was more skeptical from the beginning.
- Reality Warper: They have the power to shape reality through their thoughts.
- Really 700 Years Old: The two Ux seen in "The Battle of Ranskoor Av Kolos" barely age in 3,407 years.
- Rubber-Forehead Aliens: The only thing that distinguishes them from humans are the raised spirals on their cheeks.
- Single Specimen Species: There are only ever two Ux in existence at any one time.
- Supernatural Gold Eyes: Their eyes glow golden when they're using their powers.
Dregs (Thirteenth Doctor)
A species of apex predators native to the wasteland planet Orphan 55, where there wasn't supposed to be any life at all.
- Adaptive Ability: This is how they survived their planet's devastation, and the Tranquillity Spa security force has to have power randomizers built into their guns in order for sustained fire to be effective against them.
- It Can Think: They are smarter than they initially seem to be, with the leader breaking a Mexican Standoff involving breathing air in a sealed room by allowing itself to be put into a cage.
- Was Once a Man: Orphan 55 used to be Earth. The Dregs evolved from the humans who survived the devastation and weren't able to escape offworld.
Skithra (Thirteenth Doctor)
A species of scorpion-like scavengers who live off stolen technology from other species.
- Allegorical Character: They are a distillation of all of Thomas Edison's flaws, with none of his redeeming qualities - They both exploit inventors like Tesla for their own benefit, but unlike the merely-less-prolific Edison, the Skithra don't create anything at all.
- Creative Sterility: They steal all their technology and not only refuse to invent anything themselves, but kidnap brilliant minds from other species to figure their tech out for them.
- Hive Mind: They have one centred on their queen, so if she dies they all go down.
- Insufficiently Advanced Alien: They steal all their technology and refuse to invent anything themselves. If they need a repair, they'll abduct a suitable engineer from elsewhere.
- Red and Black and Evil All Over: Mostly black, with red highlights.
- Red Eyes, Take Warning: Most of them except for their queen have glowing red eyes, even when disguised as humans.
- Scorpion People: They are giant scorpions with energy weapons in their tails, although the Queen is much more humanoid in appearance.