While Doctor Who might be primarily seen as a family-friendly science fiction show, that doesn't mean that there aren't times when it has become incredibly dark and even scary. The show's creators have bought us some episodes that put the spooks into everyone.

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Doctor Who's greatest episodes take place when there is a  major threat. Throughout the long and storied history of the show, there have been some amazing villains for the Doctor to go up against, from creepy aliens to the most dastardly humans. While some of the villains have looked ridiculous and been anything but scary, others have had audiences hiding from behind the couch, peeking through their fingers. In this list, we will be ranking ten episodes of Doctor Who that had people doing just that.

"Mummy On The Orient Express" (2014)

Clara and the Twelfth aboard a train in Doctor Who

We kickstart the list with one of the most recent scary episodes, "The Mummy On The Orient Express." This episode brought one of the classic horror characters to life in the Doctor Who world, in the form of a malevolent mummy.

The team did an amazing job creating the visual effects for the mummy in this episode, making it appear as scary as possible while also working on a brilliant storyline to go along with it. Watching passengers and staff being slowly killed off on the train was spine-tingling. The timing of The Mummy's killings kept the viewers on edge, as they waited for the next moment that the creature would pop up again.

"Fear Her" (2006)

The Tenth Doctor and Rose walking through a narrow alley in Doctor Who

There is just something incredibly creepy about a young child singing in a scary manner, isn't there? This is a tactic that is used in many horror movies, most notably the A Nightmare On Elm Street franchise. In the Doctor Who episode "Fear Her," it is used once again.

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In this episode, children within a neighbourhood are starting to go missing. It turns out that the disappearances are being caused by one girl, who has an extraordinary ability: she can send anything she draws to another realm! It was the fact that the story was set in an ordinary neighborhood that made it so incredibly scary. Viewers were able to relate to the horror of children going missing and the manner in which the entire episode was presented only intensified the scares throughout.

"The Waters Of Mars" (2009)

An infected member of the Bowie Base One crew looks on from Doctor Who

Once again David Tennant was thrown into an incredibly creepy episode with "The Waters Of Mars," which was actually one of his final performances as the Time Lord. Taking place on the Red Planet, the Doctor quickly worked out that the planet was in terrible peril.

While he can usually save the day, there's little he can do in the face of 'The Flood,' which has got into the water supply and infected the crew of the base, leading to something that resembled a zombie outbreak. One of the biggest reasons this episode is so scary was the make-up that was used for the infected victims. It's a disgusting, brilliant visual, some of the best make-up the show has employed to date.

"The Caves Of Androzani" (1984)

A much older episode than those that have been on the list so far, but that doesn't make it any less scary. 1984's "The Caves Of Androzani" helped build Doctor Who's reputation as a show that could easily put the fear into anyone.

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This episode is full of action and keeps viewers on their toes throughout. The Doctor and Peri are poisoned and the Doctor being forced to go alone in order to get the cure to save them. It's very tense and frightening, while antagonist Sharaz Jek (who isn't the easiest on the eye), proves to be a relentless menace.

"Terror Of The Autons" (1971)

To step further back into the archives of the show, "Terror Of The Autons" was a classic episode. It's packed with reasons to be scared, from evil dolls to plastic shop dummies being brought to life. Dolls are a huge horror trope (just ask a certain Good Guy by the name of Chucky) and the concept was pulled off with aplomb here.

Another reason that the episode is so good is that it features The Master, a character that always seems to bring in superb episodes of the show. The Doctor's arch-enemy tries everything in his power to take him down, just to add another element of tension to the mix.

"Heaven Sent" (2015)

With the episode being set inside a haunted castle, "Heaven Sent" was always going to be a spooky outing. As it turned out, it was one of the Eleventh Doctor's most frightening.

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Peter Capaldi's Doctor is trapped inside a sort of purgatory in this installment, which was praised as perhaps Capaldi's best in the role. Here, the Doctor was chased by a shrouded creature that was desperate to kill him. The dark elements really helped to make this one scary, especially for any younger viewers.

"Midnight" (2008)

"Midnight" first aired in 2008, during David Tennant's run as the Doctor. It was yet another creepy episode that had viewers cowering behind the sofa. While there was nothing frightening about Lesley Sharp's character on the surface, it was the way she acted that put the fear into people.

This episode was almost like a horror movie, seeing Sharp's character possessed by an unidentified being. She provided some incredibly creepy visuals as she copied everything others did, quickly developing to the point where she could recite what the Doctor would say before he himself could say it! The fact that the Doctor had no idea what the entity was made things truly horrifying, as he usually has all the answers. Meanwhile, the other passengers with the Doctor begin fearing the worse, panicking, and turning on each other in this confined space, which only ramps up the intensity even further.

"The Empty Child" (2005)

An image of The Empty Child pointing to a figure off-screen in Doctor Who

Everything about this episode was creepy, from the setting to the child constantly asking "Are you my mummy?" The first installment of this engrossing two-parter ticked every box in the creepy department and left viewers at home terrified.

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Set during the London Blitz, the show created a monster through an 'empty' child with a gas mask, which provided a very creepy visual to start with (even before viewers learn the truth about him). The entire episode was Doctor Who at its very best, providing a great balance between scares and story. The second part of this story, "The Doctor Dances," provided the thrilling conclusion.

"Asylum Of The Daleks" (2012)

It would just have been wrong not to include an episode featuring the Daleks, wouldn't it? The Daleks are well known around the world and are considered to be the Doctor's most formidable and iconic enemies.  The action is always intense whenever they make an appearance.

In "Asylum Of The Daleks," the Doctor encounters a group of the creatures that are even scarier and more unpredictable than normal. The episode features different varieties and designs of Dalek from throughout the show's half-century history, all adding to an atmosphere that was incredibly foreboding.

When it comes to scary episodes of Doctor Who there is one that easily takes the crown:  2007's "Blink." This isn't just a contender for the scariest episode ever, but it is also one of the greatest, with the Weeping Angels being utilised to full effect.

While these monsters did return several times, their first appearance was by far the greatest. They're some of the most iconic villains the show's ever seen. Interestingly, David Tennant's Doctor only played a supporting role in this episode, communicating with Sally Sparrow through DVD clips. It was Sally who had to deal with the incredibly creepy statues that attacked at lightning speed whenever someone blinked (the creatures' odd biology renders them immobile and invincible whenever they're being observed). The pacing, jump scares and atmosphere of "Blink" made it a Doctor Who masterpiece.

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