Doctor Who ranks among the greatest and most influential sci-fi TV shows of all time. Both the classic series that ran from the 1960s through the 80s, as well as the modern reboot, have enthralled science fiction fans and inspired creative minds with their narratives, characters, and wide array of alien life forms both friendly and vicious.

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Since its reboot in 2005, the series has occasionally treated viewers to some truly terrifying creatures. From pirhana-like creatures that live in the shadows to the Doctor's most ancient enemy, these aliens, monsters, and other terrifying entities took center stage in some truly nail-biting modern Doctor Who stories.

Updated December 22, 2021 by Demaris Oxman: Flux brought fans of Doctor Who new adventures, new mysteries, and even more terrifying monsters — as well as the triumphant return of a few fan favorites. The Doctor and her companions faced new terrors in the form of the Ravages and many others, all while contending with Sontarans and other familiar threats in ways they never had before. Now that the series is over and a new one is on the horizon, it seemed a fitting time to update this list with a few additional entries. Some appeared in Flux to horrify fans, while others had simply been overlooked in the original version of this article.

10 The Silence — Various Episodes, S6

A Silent in Doctor Who

There's always something eerie about having gaps in one's memory, and that's exactly what the Silence does: the instant someone turns away, they forget having seen this creature at all. A recurring enemy in Season 6, the Silence terrorized Amy, Rory, River, and the Eleventh Doctor, all with the end goal of using River to kill the Doctor.

Though the Silence are only perceived while one is looking at them, those who encounter them retain their ideas and suggestions once they have forgotten the experience itself. This allows the Silence to expertly manipulate and brainwash humans without their influence ever being known. The show implies that they have had a hand in many aspects of human history — but we would never have any way of knowing or stopping them.

9 The Space-Suit Zombies – S9 E5, "Oxygen"

space suits with dead bodies in them

Unlike most on this list, this formidable threat wasn't a monstrous alien. In this episode, our heroes faced off against "smart" space suits intent on terminating their organic components — or, in other words, killing their occupants and everyone else on the space station. Though the real foe is neither the suits nor the corpses in them, it's easy to forget that when Twelve and his companions, Bill and Nardole, are short on oxygen and running for their lives. Glassy-eyed corpses in mechanical suits are intent on their deaths, horrifically evocative of outer-space zombies.

In the end, it turns out that the true enemy is late-stage capitalism: the deaths were ordered by corporate head honchos when the workers' lives were no longer profitable. Both the episode's monsters and its dystopic future are chilling, and hopefully left audiences thinking long after the credits rolled.

8 The Daleks – Various Episodes

dalek possessing Lin in "Resolution"

With their robotic voices and tin-can suits, Daleks have long been regarded among the more comical of Doctor Who supervillains. The 2019 Christmas special "Resolution," however, reminded fans of just how terrifying these creatures could be. Outside their metal obelisks, these creepy tentacled monsters took over human minds and demonstrated their true capacity for evil.

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In "Resolution," a dormant Dalek is reawoken and attaches itself to an archaeologist, taking full control of her mind and body, attempting to use her in its plot for world domination. The 2021 New Year's special "Revolution of the Daleks" expanded on this concept, demonstrating the horror that could befall the human race should huge numbers of Daleks possess human minds. These episodes reestablised the fearsome reputation of the ancient enemies of the timelords, and had viewers truly fearing for the safety of the Thirteenth Doctor and her friends.

7 The Gas-Mask People – S1 E9-10, "The Empty Child/The Doctor Dances

People with gas masks for faces in Doctor Who

For the most part, the first series of the Doctor Who reboot was campy and fun. Its relatively low budget meant less-than-immaculate special effects, leading to over-the-top aliens and sometimes comical villains. For the first half of the 2005 series, even the more intense episodes weren't exactly scary. But that all changed with "The Empty Child," in which a little zombie boy in a gas mask wanders war-torn London, one question on his lips: "Are you my mummy?"

As others are affected by the same condition, Rose and Nine scramble to avoid these creatures and find a way to save the day. But unlike the case with many creatures on this list, this enemy ultimately wasn't malevolent in nature, despite its terrific creep factor. The two-part story managed to find a happy ending — "Just this once, everyone lives."

6 The Beast – S2 E8-9, "The Impossible Planet/The Satan Pit"

The_Beast_(Doctor_Who)

In the latter episode of this two-part story, this sinister creature explains to the Doctor that it is an amalgamation of many religions' different concepts of evil, an embodiment of all devils and demons. Trapped in the center of a planet, it possesses and maniupulates a crew of humans and their Ood slaves to try and free itself.

It's hard to get scarier than the Devil itself. The Beast is one of the few one-off creatures in Doctor Who that is undeniably evil, not just dangerous because of its hunger or fear. Throughout the episodes, it taunts Rose, the Doctor, and the other humans; it uses the helpless Ood as tools for its evil plans. Though Rose and the Tenth Doctor ultimately escape, it's not without loss.

5 The Vashta Nerada – S4 E8-9, "Silence In The Library/Forest Of The Dead"

a skeleton after being consumed by the vashta nerada

Ever been afraid of the dark? Plenty of Doctor Who fans were after this Series 4 two-parter. While many remember these episodes for introducing the incomparable River Song, the horrific monster that appears here deserves recognition as well. The Vashta Nerada feed on human flesh, stripping it down to the bone. As the episodes reveal, the titular Library was built from wood that formed the Vashta Nerada's breeding grounds, and the building's shadows were in fact these deadly creatures.

These creatures are microscopic, but appear as shadows when in high enough concentrations to kill. The concept of the Vashta Nerada is a brilliant one — it relies not on scary visuals, but on taking a common psychological human fear and turning it into something truly deadly. Plenty of viewers slept with the lights on after watching these episodes.

4 The Grand Serpent — Various Episodes, S13

The Grand Serpent in Doctor Who Flux

Sinister and power-hungry, this foe is chilling because he reminds viewers of the twisted, cutthroat things that beings across the universe will do for the sake of advancing themselves. What's more, any viewers with a fear of snakes felt immediately justified upon seeing the undulating creature in the back of the Grand Serpent's throat.

Cold and calculating, the Grand Serpent is an eeries presence and a horrific enemy to have, killing his victims in a horrifically grotesque manner. Even more unsettling, his motives are not completely clear even by the end of Flux. Though he's currently exiled alone in space, it's entirely possible that he could return one day to complete whatever sinister plan he attempted to set in motion on Earth.

3 The Weeping Angels – Various Episodes

Weeping-Angels-Doctor-Who

Shudders run down spines of Whovians worldwide upon seeing angel statues even in the real world. Don't take your eyes off these stone creatures for even a split second — to do so allows the Weeping Angel to kill their target, feeding off their life energy. The Angels hide their faces in their hands, but when they reveal them, they show their horrific fangs and grim expressions. Doctor Who doesn't use jumpscares often, but the ones the Weeping Angels offer are effective and skillfully done.

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The Angels' terrifying first in Series 3 appearance cemented "Blink" as one of the most iconic episodes of the revived series. As they reappeared time and again during Matt Smith's era, they grew in power every time. For some fans, they eventually started to feel like something of a gimmick, but their terrifying design and eerie powers leave an impression as one of the scariest Modern Who creatures. This feeling only intensified after their dramatic return in Flux. Viewers saw an angel taking over a woman's mind and body, while other angels terrorized a small town.

2 The Flood – 2009 Special, "The Waters Of Mars"

A person overtaken by the Flood

The Flood appeared only in one special back in 2009, and yet the memory has horrified fans ever since. The main antagonist in the episode "The Waters Of Mars," this alien virus kills off the crew of Mars' Bowie Base 1, turning its victims into decaying, zombie-like creatures with water seeping from cracks in their skin.

This episode is terrifying not only for the monstrosity and visual horror of the Flood, but for the Doctor's demeanor and the way it changes over the course of the episode. He moves from a grim acceptance of the Bowie crew's fate, to a desperation and almost crazed determination for the laws of time to obey him. Ultimately, Ten's own actions are the cause of the crew captain's fate. The Flood nearly pushed the Doctor to take his own power too far — and the series has shown what happens when Time Lords interfere too much.

1 The Midnight Monster – S4 E10, "Midnight"

Tenth Doctor talks to possessed passenger

Of all the horrifically designed, power-hungry, cruel-natured villains of Doctor Who, the most terrifying monster in the modern series has neither a name nor a face. Yet there's no doubt it's sinister, considering the entity killed those in the shuttle's cockpit and possessed a passenger, Sky. Sky's eerie behavior in her possession increases audience tension and fear, without ever showing the creature itself. Suspicion among the passengers causes them to turn on each other rapidly, all too eager to sacrifice each other to save themselves.

In the end, the fear of the unknown truly makes this monster terrifying. Whether it's basic hunger or world domination, most Doctor Who antagonists have a clear motive that's revealed eventually. "Midnight" ends in mystery; the audience will never know what the creature was or why it killed its victims.

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