Time travel is an inherently fun concept. It allows characters in movies to visit the past to see where we've been or hop into the future to see where the world and society is headed. It also lets loser stoners cheat on their history report or sets off events that make the real world at large clamor for hoverboards despite the fact that those things would be ridiculously dangerous.

But it isn't all fun and fending off your teenage mom's sexual advances. Sometimes writers and directors use time travel as a mechanism for horror, and it can work surprisingly well. It also functions on different levels, including sweeping changes to the timeline or intimate, existential terror. Time travel as a narrative device offers a wealth of options and possibilities and gives audiences even more reasons to be afraid.

Just a note: We're being pretty liberal with our definition of "time travel" in this article and including things like Groundhog Day-style loops. But we're not including the version that we're all doing constantly -- that is, moving forward at regular speed -- because that would basically let us use any scary movie ever. And that just sounds like cheating. But the films below all involve some kind of temporal non-linearity, which is good enough for our purposes.

Regardless, here are 17 movies that were as scary as they were wibbly and wobbly.

17. Star Trek: First Contact

Star Trek First Contact

The scary part in the eighth Star Trek film doesn't come from the time travel itself, although the Enterprise crew does have a moment of terror when it sees an alternate version of Earth that the cybernetic Nazis, the Borg, have assimilated into their collective hive-mind of body horror. Instead, most of the frightening bits come from the fact that this is essentially a zombie movie set in space.

That sounds like a really terrible idea on its face, but First Contact is one of the better entries in the largely disappointing Next Generation films. And that's largely due to the horror elements and their juxtaposition with the otherwise hopeful thread of discovery and adventure, thanks to the b-plot that shows the titular first contact between humans and Vulcans. But mostly, the Borg are scary as hell.

The on-ship sections follow the undead-outbreak format almost slavishly, as Captain Picard (Patrick Stewart) sees members of his crew in the early stages of "infection" and kills them before they can turn completely. Audience surrogate Lily Sloane (Alfre Woodard) even describes the Borg as "cybernetic zombies." And the parallel is pretty apt, although the sci-fi villains' means of conversion involves shooting machines into your neck that eventually cause mechanical components to erupt from your skin, so we'd want Picard to shoot us, too.

16. The Jacket

Adrien Brody in The Jacket (2005)

The act of traveling through time isn't the scary part in The Jacket; it's more the circumstances and method involved. And that would be asylum doctors injecting you with a ridiculous cocktail of drugs, binding you in a straitjacket, and locking you into a morgue drawer for hours at a time while you lose your damned mind.

We're even less sure of this method's therapeutic applications than we are of how exactly it causes time travel, but we're neither medical doctors nor Doc Browns. The patient, Jack (Adrien Brody), goes 15 years into the future where he befriends Jackie (Keira Knightley), a woman whom Jack had helped in the "present," when she was a child. And while things eventually work out just fine for everyone, the claustrophobic part of us isn't sure that the time we spend hanging out in a dark drawer, unable to move, drugged out of our skulls and waiting to go back to the future, is really worth it.

15. Army of Darkness

Ash in Army of Darkness

Admittedly, the second sequel to director Sam Raimi's The Evil Dead makes the transition to full-on comedy by the time hero Ash Williams (Bruce Campbell) kills his first Deadite, but we're including it because it still never quite abandons its horror roots. And we don't just mean the ones that failed to keep the second movie's possessed tree from flying into the time portal along with Ash and his awesome car.

Army of Darkness has the hapless demon fighter transported through time and space to medieval England, where it falls upon him to once again recover the Necronomicon ex Mortis and banish the ancient evil that plagued him in the present. On the way, however, he has to fight several tiny copies of himself and one fully grown one that emerges from his body after a mini-Ash leaps down his throat.

It's done for laughs, but that's really disturbing when you think about it, especially the part where Evil Ash starts to sprout from the original's shoulder as a single, terrifying eye.

14. Time After Time

Malcolm McDowell as H.G. Wells in Time after Time (1979)

Nicholas Meyer (Star Trek VI: The Undiscovered Country) wrote and directed this 1979 film that has writer H.G. Wells (Malcolm McDowell) using his time machine to pursue Jack the Ripper (David Warner) to contemporary San Francisco. Its plot of temporally displaced travelers having more or less a romp through The City by the Bay seems like a prototype for Meyer's later, more successful script, Star Trek IV: The Voyage Home, but this one raises the immediate stakes by setting one of history's most famous killers loose in the present.

While it stays pretty light and doesn't completely devolve into slasher territory, Warner manages to pull off some unsettling moments as he comments on the dangerous new era he's explored. "The world has caught up with me and surpassed me," the Ripper says, showing a horrified Wells the cavalcade of non-stop violence on American TV. "90 years ago, I was a freak. Today, I'm an amateur."

Of course, if all that sitting around and talking isn't scary or gruesome enough for you, we're pretty sure that the upcoming ABC television series adaptation will pick up the slack. And then it will probably cut that slack with a very sharp, very bloody knife.

13. Source Code

Jake Gyllenhaal in Source Code

Like First Contact, the scares in Duncan Jones' (Warcraft, Moon) Source Code don't come from the journey itself, but rather the circumstances. Jake Gyllenhaal plays Colter Stevens, an Army pilot who Quantum Leaps into a teacher named Sean Fentress -- who had died in a terrorist attack on a train -- and he's tasked with preventing an even larger attack on Chicago. It's a really complicated set-up, but basically, Stevens decides he wants to prevent the first incident and save everyone on board, especially Fentress' traveling companion Christina (Michelle Monaghan) because she's so pretty. But his Air Force handlers say that would be pointless because everyone in the reality he's experiencing is already dead; he is only there to relive his host body's last eight minutes of life to identify the bomber and prevent an upcoming attack from happening.

This is a very confusing movie, and it gets even more so at the end when Stevens successfully changes the past. But that's only after we discover two things. The first is that the Quantum Leap parallel is totally intentional because Scott Bakula, who starred in that TV series, has a voice cameo as Stevens' father. But that's neither here nor there; we just nerded out when he said series hero Sam Beckett's catchphrase, "Oh boy."

The second, more relevant reveal is that while Steven's perspective shows him entering the past from a metal capsule, in reality, he's little more than a torso and a head hooked up to life-support in a box. He "died" in Afghanistan two months before the start of the movie, but the Air Force is keeping him alive because his biology is similar enough to Fentress' for him to make the trip back in time. It's a deeply disturbing image, and as far from Doctor Who's super-fun TARDIS as you're likely to get in a time-travel movie.

12. Lost in Space

Deadly, alien spiders in Lost in Space (1998)

The 1998 film adaptation of the cheesy, '60s sci-fi series about the Robinsons -- a family that is ... well, it's right there in the title -- is an early example of the "gritty remake." While the original was light, silly, and even campier than its rival, Star Trek, the movie is still mostly fun but includes a plot that has the usually ineffectual Dr. Smith (Gary Oldman) mutating into a giant spider monster and murdering most of the other characters before planning to unleash his brood upon Earth.

That's in an alternate, future timeline, however. Our heroes discover a planet covered in portals and bubbles due to an older version of Will Robinson (Jack Johnson, Jared Harris) trying to build a time machine to prevent his family's fateful trip from ever happening and therefore save his mother, father, sisters, and maybe even Matt LeBlanc's character if there's time, from their painful, deadly encounters with cosmic chelicerae.

It's not the time travel that's scary here so much as it is the evil, future version of Dr. Smith, who's mostly just a spooky guy in a cloak, skulking around like a villain in Star Wars, but then at the end, he whips it off to reveal an inexplicably long neck, several extra limbs, and a pulsing, ripe egg sac. It's like Lego released a set called "Your Nightmares," and Spider Smith is the bricks.

11. Predestination

Ethan Hawke in Predestination

Based on "All You Zombies," a short story by Robert Heinlein (Starship Troopers) Predestination is a really bizarre film that appears to have six significant characters -- a mad bomber, a time agent posing as a bartender, his boss, a man, a woman, and a baby -- but by the end, viewers learn that in fact, the movie only has two. That's because the bomber, the time agent, and the man, woman, and baby are all the same person at different points in their amazingly convoluted life.

The title comes from the idea of a predestination paradox, which involves an attempt at using time travel to try to change events in the past only for it to turn out that the traveler's actions caused them to happen in the first place. So this is kind of like The Terminator but with fewer robots and way more biology.

Predestination and its source material also posit that if you go back in time and impregnate your past, opposite-gendered self, you will be the result of that union. Obviously, we can't test that hypothesis because intersex conditions are kind of rare, and time travel is (as far as we know) impossible. But we'll give the respective writers of the story and film the benefit of the doubt because it makes for some interesting drama.

Like a few other entries on our list, not every viewer will see the scariness here. But you're a fan of the idea that you are in control of your own destiny, a movie about a person confronted with the knowledge that every moment of their existence has and must occur according to a strict plan is a pretty scary thought.

10. Primer

Aaron and Abe working in Primer.

Writer, director, editor, composer, and co-star Shane Carruth's hyper-scientific movie Primer depicts an accidental discovery of a time-travel device by two scientists who are trying to create a means through which to decrease an object's weight. That is, itself, an impressive project, but we suppose inventing a temporal manipulation field isn't too shabby as mistakes go.

It comes with a catch, however, because messing with the continuum always does. The "box" creates a field  that causes objects inside it to travel to times at which the field is active. This means that if you turn on the device at noon, enter it at 6 p.m., and wait six hours, you will emerge back at noon. We needed helpful charts like this one to understand the process completely, but we think we get it now. But the main point is that longer trips are more difficult due to the fact that you have to wait in the box the full duration of your trip.

Primer is an intentionally ambiguous and vague movie, but that only adds to the horror of its implications. It ends with one of the scientists going a bit evil and starting construction of a "box" the size of a building. We're not sure what he plans to do with that thing, but that's why it's unsettling: He's clearly up to no good, and his options are wide open.

9. 12:01 P.M.

Kurtwood Smith in 12:01 p.m. (1990)

Being stuck in a time loop can be fun, provided you have time to learn the piano and play with a famous groundhog, but hilarity is not guaranteed. And we're not just talking about that episode of Star Trek: The Next Generation in which the Enterprise blows up almost a hundred times.

In the 1990 short film 12:01 p.m. (not to be confused with 12:01,  the less interesting, feature-length 1993 adaptation of the same story by Richard Lupoff), Kurtwood Smith (That '70s Show, Robocop) plays Myron Castleman, a guy who realizes that he is inexplicably repeating a single hour of his life, starting just after noon.

Eventually, Castleman learns of a scientist named Rosenbaum who described the phenomenon he's experiencing. He spends several loops trying to get in touch with the theorist, describing his situation, convincing Rosenbaum he's not crazy, and asking him for help to break the cycle. But the bad news is that Castleman is stuck. This upsets him so much that he shoots himself ... and the next thing he knows, he's snapped back once again to the start of the loop.

Like Time Lapse, 12:01 p.m. provides more of an existentially terrifying experience, but it's still a scary concept. And many office workers like Castleman feel like they're endlessly repeating the same day every time they go to their job, so it's not even a completely alien concept. But at least the main character in the movie gets trapped around lunchtime, right?

8. Haunter

Abigail Breslin in Haunter

This spooky film by director Vincenzo Natali (Cube, Splice) stars Abigail Breslin as Lisa, a moody teenager whose moodiness is pretty well deserved: She's a ghost forced to relive the same day in 1985 repeatedly -- the day she and her family died -- while everyone else carries on, unaware that anything is amiss.

Haunter starts as a time-loop movie and then transitions into a full-on Quantum Leap situation as Lisa learns she can transport herself into the body of Olivia, another girl who lives in the house in the modern day. But she also learns that she's not the only entity capable of doing so; the man who killed Lisa's family, Edgar Mullen (Stephen McHattie) has been haunting and murdering the inhabitants of the same house for decades.

The story gets increasingly ridiculous as it goes, but it's an interesting take on the idea of a haunted-house movie from the ghosts' point of view. It contains some decent scares, and McHattie plays the murderer with the right balance of mystery, perverse glee, and pure evil.

7. Time Lapse

Three friends discover a time-traveling camera in Time Lapse (2014)

This sci-fi equivalent of director Danny Boyle's Shallow Grave has three friends (Danielle Panabaker, Matt O'Leary, George Finn) discovering a gigantic, strange camera that takes pictures of events 24 hours in the future. Obviously, their first impulse is to use this amazing technology for personal gain, with one of the three making money from gambling and another, an artist, using the images of the future to break his creative block.

But because dangerous, world-changing power has a habit of turning everyone into jerks and ruining their lives, the three find themselves trapped when they find out that they have to fulfill the futures they see in the images, or they'll create a paradox and, we don't know, die, probably.

This isn't a horror movie by any stretch, but it generates some terror from the idea of having basically a time machine but still being inexorably stuck to the events it depicts. And some developments later on -- other than the ones the Time Camera spits out daily -- throw in some betrayal and further confusion to make sure you feel completely terrible by the end of the story.

6. The Caller

Rachel Lefevre in The Caller (2011)

Nobody actually travels through time in 2011's The Caller; it's more like a scarier version of Frequency in that people living in the same place in different eras are able to communicate with each other. But The Caller has way less father-son reconciliation and more murdering and graphic child abuse.

Mary (Rachelle Lefevre) discovers that the quaint, antique phone in her new apartment lets one of its earlier tenants, Rose (Lorna Raver) speak to her from decades in the past. This could be a good setup for some hijinks, but Rose's calls get increasingly disturbing until Mary starts to fear for her life.

It's a clever setup, since Rose (in the past) quickly becomes threatening to Mary (in the present), and you realize how difficult it would be to protect yourself from a crazy person living in the past. In one of the most disturbing and effective scenes, Rose tracks down Mary's younger self and disfigures her, and the present version has to suffer all of the pain of the now-old injuries all at once.

This angle, combined with the fact that Rose, a disembodied voice on a phone, manages to be completely menacing and terrifying, makes The Caller a super-creepy, lesser known gem.

5. The House at the End of Time

Ruddy Rodríguez in The House at the End of Time (2013)

Venezuelan director Alejandro Hidalgo's only movie (so far), The House at the End of Time is a Gothic horror story with a time-bending twist. It's atmospheric, disturbing, and ultimately moving and beautiful, but you have to suffer some trauma to get there.

In 1981, the main character, Dulce (Ruddy Rodríguez), discovers her husband dead from a stab wound in the basement of their haunted house. With no other suspects, she is arrested, convicted, and jailed for 30 years for the murder, at the end of which the court sentences her to permanent house arrest at the scene of the crime. And that's kind of messed up if you think about it.

The story switches between modern-day Dulce and her past self in the time leading up to the murder, along with the frightening, supernatural phenomena plague them. It's the genre-standard bumps and knocks in the night, but for some reason that stuff is usually way scarier in Spanish.

Ultimately, the two storylines converge in interesting ways, leading to a satisfying, clever, and emotional conclusion. So really, all of that terror was worth it.

4. Triangle

Melissa George in Triangle (2009)

This surreal horror film from director Christopher Smith (Black Death, Severance) stars Melissa George (Mulholland Drive) as Jess, one of a group of friends whose boat outing takes a bad turn when they board an abandoned ocean liner, and creepy things start happening. And then violent things start happening when a masked killer starts trying to kill everyone.

But it's all part of the time-messery, since the killer is just a future version of Jess who is trying to "break the pattern" that keeps everyone stuck on the ship, doomed to die horribly over and over. Even weirder, events persist across repetitions, so one wounded woman crawls away from her attacker and ends up dying on a huge pile of her dead former selves, remnants of countless earlier loops.

Triangle is a pretty strange movie, as creepy as it is fascinating. And even the biggest of time-travel nerds will find themselves at a loss to understand it all.

3. Timecrimes

Timecrimes Spanish Time Travel Movie

Spanish director Nacho Vigalondo's less ridiculous version of a hot tub time machine sends middle-aged Héctor (Karra Elejalde) back about an hour. And that shouldn't be enough to get into too much trouble, but he manages, thanks to the looming threat of a mysterious man whose head is covered in pink bandages and his own general misunderstanding of temporal mechanics.

Timecrimes -- the Spanish title is Los Cronocrímenes, but we prefer rhymes to alliteration -- swings wildly between odd humor, horror, and tragedy, but it somehow manages to hold together admirably. It's a pretty small movie; it only has four characters, including Vigalondo himself as the scientist who created the device that will, has, and does set things into motion, but its clever plot and surprising developments make it enthralling, fun, and at times tense and chilling.

One smart reveal later in the movie will have you immediately going back to check for a clue in an earlier scene, and sure enough, it's there. And the fact that we don't notice it until Vigalondo specifically shows it to us is just one of Timecrimes' great achievements. It's right up there with its ability to make the color pink scary.

2. Donnie Darko

Donnie holding a knife in Donnie Darko

Even if Frank the Bunny, the creepy harbinger of doom in Donnie Darko, weren't a time-traveling ghost, he'd still be terrifying because look at that suit.

The movie is about a teenager (Jake Gyllenhaal, returning to our list) whose behavior becomes increasingly troubling and dangerous after he starts receiving instructions from the guy in the scary suit. The rest of the story makes even less sense than that, and you kind of have to read the in-universe book, The Philosophy of Time Travel, to figure out what exactly is going on. And even then, it's kind of confusing.

Basically, Donnie's having his weird experiences because a temporal incident has caused a disruption, leading to the creation of a "Tangent Universe"; his job is to fix the problem before it creates a black hole that could destroy everything. And even less fortunately, the film implies Donnie's in a time loop and has to keep trying until he gets it right, and the solution involves his own death.

The more you think about it, the more clever and scary Donnie Darko becomes. Absolutely everything that happens, including the seemingly throwaway scenes and acts, contributes to the Tangent/Primary Universe resolution, and it's not often that we've seen a movie crafted so deliberately. But meanwhile, it's all pretty upsetting, and understanding exactly what's going on only increases the chrono-panic.

1. The Terminator

Kyle Reese The Terminator

Writer/director James Cameron's 1984 sci-fi classic offers both an apocalyptic future full of killer robots and a present in which one of them shows up in Los Angeles and just starts murdering everybody. Both are pretty frightening.

If you haven't seen The Terminator (or any of the four sequels or the Sarah Connor Chronicles spin-off TV series, all of which reiterate the plot of the first film) it's about two beings who are sent back in time -- one is tasked with defending humanity's future, while the other is sent to destroy it. Also, you really need to see The Terminator; what have you been doing?

Anyway, the literal killing machine is there to take out Sarah Connor, who will give birth to John Connor, the leader of the human Resistance, thus destroying the future before it happens. But the end reveals that by sending the Terminator back through time, evil computer system Skynet only ensured its own destruction. The soldier sent back to protect Sarah, Kyle Reese, is John's father, and the entire reason the future general knew how to combat Skynet and the Terminators is because the film's events give Sarah plenty of time to prepare both herself and John for the war.

If Skynet had done nothing, it would have won, but the second movie reveals that Skynet wouldn't have existed without the remains of the original Terminator, and one of the few things more frightening than an unfeeling cyborg that knows nothing but murder is the idea that even in a universe with time travel, we are powerless to change anything.

The sequel tries to walk that back with its "No fate but what we make for ourselves" motif, but that just felt like a way to justify was has to be considered one of the best action movies ever made.

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Did we miss any of your favorite time travelling fright flicks? Let us know in the comments!