Top 30 Scariest Movie Aliens

Top 30 Scariest Movie Aliens

Welcome to WatchMojo, and today we’re counting down our picks for the most spine chilling, horrific extraterrestrials to ever grace the silver screen.

#30: The Mimics
“Edge of Tomorrow” (2014)
The stakes in “Edge of Tomorrow” are epically high. An unstoppable alien army has crash-landed in Europe, threatening to spread across the globe. The Mimics are incredibly intimidating. Their bio-mechanical design gives them an otherworldly presence and the ability to burrow through the ground like a hedgehog made of knives. In battle, the armies of humanity have suffered one defeat after another. As it turns out, that’s because these alien killing machines have control over time itself. The Omega Mimic can pull a “Groundhog Day” when its Alpha generals are killed. That knowledge of the future allows the Mimics to repeat battles over and over until victory is achieved.

#29: Aliens
“Communion” (1989)
This lesser known sci-fi horror film is based on a book by Whitley Strieber about his own alleged encounter with aliens and subsequent ‘flashbacks’. The film stars Christopher Walken as Stieber at his unhinged best. It straddles the line between slapstick and horror. On one hand, Walken spending a surprisingly large amount of time dancing with the aliens he meets … On the other hand, there are truly frightening scenes like the one where he removes the face of a Grey to reveal the slimy creature beneath. All in all, the film feels like a bad 1980s acid trip, leading the viewer to share in Streiber’s confusion and uncertainty.

#28: Alien Beasts
“Attack the Block” (2011)
Humans have been encountering creatures from outer space since Georges Méliès introduced us to his moon creatures in 1902. Given that aliens have been part of motion pictures throughout cinematic history, it can be tough to come up with an original concept! Enter writer/director Joe Cornish and “Attack the Block.” A meteor crashes into a public housing council estate, releasing a horde of alien beasts. The residents of the block - including a teenage street gang - must defend themselves and their neighbors from the threat. Imagine spikey, eyeless space wolf/gorilla hybrids with glow-in-the-dark jaws, and you’ll have the right idea. The beasts are killing machines, and only the ingenuity of the residents helped them survive the night.

#27: The Strangers
“Dark City” (1998)
“Dark City” is one of the most under-appreciated films of the 1990s. As protagonist John Murdoch navigates the city and his own distorted memories, he discovers the truth: the pasty white men, the Strangers, chasing him over this noir landscape aren’t men at all. They are psychic aliens, using their powers, hive mind, and machines to run experiments on human test subjects. The city isn’t a city, either, but a giant vessel in space. The creatures are dying from an unknown cause and hope that extracting the secret of human individuality will cure them. The Strangers are the unseen power behind the world of the film, manipulating events and people for their own dark ends.

#26: The Shimmer
“Annihilation” (2018)
We humans tend to anthropomorphize everything in fiction - including aliens. We ascribe human thought and motivations to characters so that the audience can better understand what’s happening. But in Alex Garland’s 2018 adaptation of Jeff VanderMeer’s novel “Annihilation”, the alien presence at the center of the story is alien in both mind and body. The Shimmer’s motivations are completely unknown, so the audience is left only with the results of its actions. The Shimmer is a catalyst of change, warping and altering everything it touches. Change can be terrifying, especially when it’s a change that results in the annihilation of what existed before. This more existentialist horror is what makes the Shimmer scary on a literally cellular level.

#25: Cooper
“Super 8” (2011)
What if “E.T.” were a horror film? That seemed to be the question J.J. Abrams chose to answer with his ‘kids on bikes’ classic, “Super 8.” A group of teens from Lillian, Ohio witness a violent train derailment. The crash was no accident, however. The U.S. Army was transporting a large, alien monster, and it escaped. Soon after, the residents of Lillian began to go missing. The creature is barely seen, allowing the audience's imaginations to run wild. In truth, though, ‘Cooper,’ isn’t a monster at all. He's just a wrongfully-detained interstellar traveler trying to return home. No Ohioans were harmed during the making of his spaceship.

#24: Skin Thief Alien
“Under the Skin” (2013)
The Skin Thief alien from "Under the Skin" is easily one of the weirdest roles in Scarlett Johansson’s filmography. Part road trip, part acid trip, “Under the Skin” shows the journey of her alien as she hunts men across the Scottish countryside. Once captured, the men are harvested, leaving only their skin. She’s methodical and seems devoid of emotion, although this changes as she begins to identify with the humans she was sent to prey on. Both her origins and motives are left unclear, resulting in an incredibly unsettling cinematic experience. Her cold, calculated actions and eerie, otherworldly presence make her a truly haunting and iconic cinematic alien.

#23: Jean Jacket
“Nope” (2022)
Jordan Peele’s “Nope” is a complex film examining our culture’s obsession with spectacle and violence. It’s also just an incredible horror movie. By looking up at this flying object, humans on the ground make themselves vulnerable to attack. It’s ranch owner OJ who realizes that the object is not a spaceship, but a wild animal. He and his sister Em observe its behavior, learn its weaknesses, and use that knowledge to kill it. In the interim, however, the creature - dubbed ‘Jean Jacket’ - is a blight on the countryside. When its true form is revealed, Jean Jacket appears to be some kind of giant, flying, carnivorous jellyfish. It consumes dozens of people and animals, creating a spectacle to lure in its prey.

#22: Owl Aliens
“The Fourth Kind” (2009)
The online UFO community has believed in the connection between aliens and owls for a long time. This was an idea that science fiction thriller film “The Fourth Kind” picked up and ran with in 2009. For the uninitiated, the idea is that many people who have been abducted by aliens remember seeing owls right before or after their experience. These are implanted memories that aliens have been using to hide their appearance. The film is shot in documentary style, with reenactments used side by side with faux found footage. The aliens are never actually seen on film, lending them an air of unknowable menace.

#21: Clover
“Cloverfield” (2008)
A found footage kaiju film was a great idea, putting the audience right there in the middle of the action. And that’s a big part of what makes “Cloverfield” so memorable and terrifying. The film sees a gigantic extraterrestrial wreak absolute havoc in Manhattan. While the monster isn’t often seen, the small glimpses we get are more than enough to scare the heck out of us. The entire setup makes you wonder: would we survive a giant monster attack? And the answer is: probably not! Conversely, the second film in the franchise, "10 Cloverfield Lane" is a slow-burn psychological thriller that ends with the reveal of a full-blown alien invasion! The quadrupedal figure we see there is honestly pretty scary too!

#20: Death Angels
“A Quiet Place” franchise (2018-)
There’s not a whole lot that we know about these mysterious predators, but they sure know how to make an entrance! After being carried to our unsuspecting planet by meteors, the terrifying creatures quickly brought society to its knees. They’re sometimes referred to as “Death Angels” but are most commonly labelled monsters. We think the term “nightmare fuel” is most accurate. Incredibly fast and hyper-sensitive to any sort of noise, they’ve essentially forced the remnants of humankind into quiet mode. With their long limbs, elaborate and slimy auditory systems along with wickedly sharp claws, these creatures seem tailor-made for hunting humans. And their lack of eyes only adds to their creep out factor.

#19: The Greys
“Dark Skies” (2013)
While this film got generally mixed reviews from critics, the aliens at the center of the story still made a lasting impression on audiences. With their wispy arms, hunched backs and oversized heads, the Greys are by no means the most fearsome looking extraterrestrials on our list today. But their thoroughly alien anatomy is definitely strange enough to make your skin crawl. The real reason they earn a spot here is how the filmmaker decided to portray them in the story. Subscribing to the “less is more” philosophy of horror, the greys are never fully revealed to the audience and appear in silhouettes and shadows. And when you add a penchant for kidnapping vulnerable humans to the mix, they go from creepy to downright horrifying.

#18: Brandon Breyer
“Brightburn” (2019)
In terms of alien anatomy, it doesn’t get much more unassuming than this. Brandon Breyer looks like your run-of-the-mill young boy. What he’s capable of, however, is anything but ordinary. Produced by James Gunn, “Brightburn” essentially asks the question “what if Clark Kent had turned out bad?” Brandon Breyers’s origin story mirrors that of Superman, right down to the spaceship, incredible powers and a rural upbringing. When Brandon’s powers awaken, however, the spaceship he arrived in gives him a crash course in villainy and global domination. Creepy kids always bring an extra scare factor to horror films. But Brandon’s mannerisms, predatory nature and awe-inspiring abilities take it to a whole new level. We’re very glad that Superman is historically on humanity’s side.

#17: The Aliens
“Signs” (2002)
The mention of M. Night Shyamalan ignites more jeers than cheers these days, but the once promising director gave us some unforgettable scares in the sci-fi thriller, “Signs.” Although simplistic in design, these outer space foreigners left a lasting impression on moviegoers. Who could forget the intense kitchen scene or the jaw-dropping birthday interruption footage? The horror came from what we didn’t see and Shyamalan built upon the tension to create some truly memorable moments. Let’s hope those splashes of water were enough to keep them from coming back.

#16: Sil
“Species” (1995)
Created by genetically splicing human DNA with that of alien DNA, the attractive Sil is one alien that isn’t shy about her intentions. With an unstoppable desire to reproduce, she searches for a mate, often with extremely deadly results. Strong, smart and possessing incredible regenerative capabilities, Sil is as dangerous as she is sexy.

#15: Aliens [aka Ghouls]
“They Live” (1988)
It’s a question that’s plagued many an alien enthusiast and conspiracy theorist: what if they already walk among us? In this 1988 sci-fi action horror flick, the extraterrestrials take advantage of their humanoid anatomy to pass as earthlings—albeit with plenty of help from elaborate disguises. Like many of filmmaker John Carpenter’s movies, “They Live” took time to find its fanbase. Negative reviews of the film be damned; today, these extraterrestrials are recognized for what they really are—yet another masterclass in monstrous aliens courtesy of a horror legend. With their blue skin, buggish eyes and lipless mouths, these alien invaders also earned the name they were given in the credits. There, they were called “ghouls.”

#14: Mr. Gray
“Dreamcatcher” (2003)
Based on Stephen King’s novel of the same name, “Dreamcatcher” follows a group of friends that come across a parasitic alien species that have the ability to possess an unwilling victim’s body as well as use telepathy to control their victims. The main alien antagonist, given the name of “Mr. Grey,” along with several sharp-toothed alien worms, seek to populate the planet with their larvae. But it’s his methodical and gruesome methods that make Mr. Grey stand out as well as one the fiercest aliens this side of the Milky Way.

#13: The BioRaptors
“Pitch Black” (2000)
Before he became Dominic Toretto, this sci-film gave Vin Diesel a huge leading role. A blend of sci-fi, horror and action, “Pitch Black” sees Diesel playing a surgically-enhanced ex-soldier turned criminal named Riddick. This hardened warrior and master of survival barely earns the label anti-hero. When you suddenly find yourself being swarmed by bio-raptors, however, there’s really no one else you’d rather have around. Bio-raptors are the apex predators of the barren wasteland that is planet M6-117. These creatures look like a blend of a hammerhead shark, a dragon and a very twisted imagination. With their massive teeth, razor sharp claws and prehensile tails, they’ve got multiple ways to take down prey. Thankfully, they’re sensitive to light. But honestly, that’s only a small comfort.

#12: The Killer Klowns
“Killer Klowns from Outer Space” (1988)
Is this movie cheesy? Absolutely. But it’s also a testament to just how effective practical effects can be when it comes to terrifying your audience. Now, clowns in general tend to freak people out—and this was true long before the clown panic of 2016. There’s just something so inhuman about all that makeup and the outfits. In this case, however, the titular clowns from this movie are literally from outer space. And that isn’t white facepaint, it’s their skin! Armed with all manner of weaponized, clownish accessories, these extraterrestrials live to cause mayhem and are hungry for humans. Though this movie is a horror comedy, the practical effects used to bring the clowns to life are truly grotesque.

#11: The Pod People
“Invasion of the Body Snatchers” (1978)
They might not have the most intimidating label, but these extraterrestrials make up for it with their world-conquering ways. After originating in the 1955 novel “The Body Snatchers”, the pod people have appeared in a number of film adaptations. The scariest ones appear in the 1978 version starring Donald Sutherland. The film treats us to the sight of this extraterrestrial race in their natural gelatinous form and… it’s pretty weird. What really earns them a place on our list is the way they assume the form of humans and take their place. As they spread, the pod people systematically identify the unassimilated in a bid to replace all of humankind. That scream… it will haunt you long after the end credits roll.

#10: The Grey Aliens
“Extraterrestrial” (2014)
When a group of friends decide to get together for a party at a cabin in the middle of the woods, horror movie 101 dictates that treacherous events await them. The group in “Extraterrestrial” finds themselves confronting some absolutely vicious otherworldly beings that happen to crash land nearby. If these aliens weren’t menacing enough to begin with, killing one of them certainly didn’t help the friends’ chances of survival. The sheer brutality that these aliens unleash upon these unfortunate victims is one for the record books and makes us second guess the idea of exploring other planets.

#9: The Arachnids
“Starship Troopers” franchise (1997-)
No, the CGI in this franchise is not the best. While the films can feel a bit dated, “Starship Troopers” achieved something that you never really could have using practical effects—a swarm of aliens. Honestly, the arachnids would have snagged a spot on this list simply by virtue of their size and numbers. What lands them in the top 10, however, is the fact that they’re extremely organized and—though they might not look it—remarkably advanced. The Arachnids have seemingly got an equivalent for just about every human technology. Their alternatives just happen to be organic. And it’s this impressive range of abilities that makes these “bugs” so damn terrifying. Oh, and don’t even get us started on brain bug.

#8: The Aliens
“War of the Worlds” (2005)
This tale of alien invasion is so terrifying that, in 1938, just the radio drama was enough to send some listeners into a panic. H. G. Wells’ iconic story has been adapted a number of times over the years. But the aliens made their biggest impact yet in the 2005 adaptation. Directed by Steven Spielberg, the 2005 “War of the Worlds” is truly epic in scale—with extraterrestrials to match. Though the invaders were labelled “martians” in earlier versions of the story, Spielberg decided to obscure their origins to help add to their scare factor. Not that they need it! From their creepy design to their massive machines of war and the way they “repurpose” human bodies, these aliens are earth’s worst nightmare.

#7: The Long One
“Slither” (2006)
James Gunn strikes again on our list, this time with a race of alien parasites. These creepy, slithering otherworldly creatures have various forms in which to inspire fear. In their most rudimentary, slug-like form, these creepy red creatures are fairly vulnerable. But when they work together, it’s only a matter of time until one of them finds a way into the host. The parasite at the heart of this alien race is the most grotesque of all. Known as the Long One, it takes possession of a host and quickly causes them to mutate into a mass of tentacles, weird growths and pus. Eventually, the original host becomes all but unrecognizable. This is one close encounter we’d rather not have.

#6: It
“It” franchise (1990-)
We bet you didn’t expect to see clowns appear on this list again. Or maybe you did! In which case... congratulations, you really know your space clowns. This iconic Stephen King creation, known simply as “It”, is best known for taking the form of Pennywise the Dancing Clown. With its vast assortment of abilities and near limitless power, It has terrified more than one generation of moviegoers. But this monster is more than just a shapeshifting clown. An entity that dates back millions of years, it came crashing down to earth either carried by a spatial body or in the form of one. Since then, it has plagued the people of Derry and their predecessors, and lives on a diet of fear and unlucky victims.

#5: The Extraterrestrials
“Fire in the Sky” (1993)
One would hope that our first contact with aliens will be nothing like this. The extraterrestrial beings in “Fire in the Sky” are somewhat plain-looking and don’t appear very menacing, but what makes them utterly terrifying is the way they conduct horrific and intensely painful experiments - such as the ones Travis Walton goes through. This is exactly the sort of abduction that nightmares are made of. Let’s hope that if aliens actually want to study us that it’s through more of a face-to-face conversation, not a brutal game of Operation.

#4: The Grey Aliens
“V/H/S 2” (2013)
What starts out as a fun get together with a group of teenagers strapping their camera to their lovable Yorkie quickly turns into a nightmare in this sequel to “V/H/S.” The camera captures every terrifying second as the kids are abducted one by one. Tricked by flashing lights and sirens, the kids head towards the police, but ultimately fall right into the grey aliens’ trap. We are given one last haunting image of them being taken away while their dying dog takes one last breath - and it all leaves us speechless with thoughts of space travel seeming less and less appealing with every passing moment.

#3: Predator
“Predator” franchise (1987-)
Aliens in film often fit into one of two categories. You’ve got your snarling, aggressive, animalistic creatures. And then you’ve got your mysterious technologically advanced abductors. The predator, or yautja, however, is cut from a different cloth. True to their names, they’re master predators who live to hunt, but they do it with super advanced technology that puts humans to shame. It’s this combination that makes them such a formidable force to reckon with. Their code of honor won’t stop them from going after their prey. The yautja often use cloaking technology and keep themselves masked. When a predator eventually reveals its true face, however, well... it’s rather hard to forget.

#2: The Thing
“The Thing” (1982)
John Carpenter did something special with the aliens in “They Live”. But his greatest gift to sci-fi is without a doubt “The Thing”. And that statement can equally apply in reference to the film itself and the titular extraterrestrial. The Thing is a shapeshifting creature that can not only emulate other life forms, but also actually assimilate them into its biomass. One moment, it’s posing as your friend, the next moment... it’s mutated that familiar face into something twisted, unimaginable and extremely lethal. Worst of all, it has the ability to live on even after being severed into multiple pieces. Even when you think you’ve destroyed it, some portion of the extraterrestrial threat may very well live on—just waiting to restart the cycle of violence.

#1: The Xenomorphs
“Alien” franchise (1979-)
This extraterrestrial species is so iconic that it has managed to maintain its monopoly on the word “Alien” for its franchise. It’s inspired countless notable imitators, like “The Faculty” alien. But honestly, no other creature comes close. Designed by Swiss artist H. R. Giger, the xenomorph is an unholy amalgamation of humanity’s biggest fears and anxieties. It’s serpentine, resembles human anatomy and is capable of implanting its host with a deadly parasite. This primal and predatory species seemingly exists only to cause pain. Although these aliens are terrifying in all its forms, the xenomorph is the purest and most disturbing creation found in a Ridley Scott-directed film. Its place in horror history, cinema and our nightmares has been rightfully earned. It doesn’t get scarier than the xenomorph.

Scary aliens have been a staple of film since its inception. Have any of your favorite aliens been scared off our list? Let us know in the comments below!