Science fiction has been a part of cinema since motion pictures were born. 1902’s A Trip to the Moon allowed audiences to leave this world and travel into the stars. Outer space and extraterrestrials have been a part of storytelling for generations. Films allow the viewers to see directors' interpretations of what aliens could look like and how they may interact with our world.

While films like E.T. The Extraterrestrial explore the heart and compassion of these creatures, other prominent science fiction films dive into a darker vision. These films take the question “what if” and add a horrifying twist that brings our nightmares to life, and we can’t get enough of it. These are the most terrifying aliens and extraterrestrials ever put on film, in no particular order.

Updated on August 11th, 2023, by Federico Furzan: This article has been updated with additional content to keep the discussion fresh and relevant with even more information and new entries.

13 Death Angels

A Quiet Place (2018)

A Quiet Place monster
Paramount Pictures

John Krasinski directed A Quiet Place, one of the most successful scary movies of recent years. The characters and their familial dynamic captivate the audience from the very first scene. Having great characters is a tremendous feat alone, but it's combined with some of the most gut-wrenchingly disturbing aliens put on screen, elevating the film to a higher caliber.

The unique aliens hunted by sound, which resulted in fantastic sound design. It isolated the alien noises as the humans try to keep silent, along with the toothy smile and opening face of the "Death Angel" aliens, creating great sequences of terror.

12 Xenomorph

Alien (1979)

Alien 1979 xenomorph
20th Century Fox

Ridley Scott’s Alien is one of the scariest horror films ever made. Perhaps the scariest science fiction film of all time. Alien contains many layers of scares, all derived from the claustrophobia and helplessness that these characters are experiencing.

What is truly horrific is what this creature is capable of. The Xenomorph is large, but silent in its motions, with acidic body fluids and a protractible set of teeth. These traits make it a deadly force in several great scenes that some characters are no match for. This creature has no remorse and salivates for humans to feed on. Some of the most brutal results of its attacks were actually cut.

11 Green Aliens

Signs (2002)

The alien from Signs

Signs is a family drama with extraterrestrial elements sprinkled into it. However, those moments of alien interaction are truly terrifying. M. Night Shyamalan creates a grounded environment for the audience as they begin to latch onto a grieving father (Mel Gibson), and his brother (Joaquin Phoenix). The film is a metaphor for accepting the idea that there is something greater to believe in.

While Gibson’s character struggles with his faith, he comes face to face with creatures from another world. Those creatures place themselves on the home front, making their presence known in subtle but eerie ways. These aliens remain unseen for most of the movie and yet still fill it with dread, but when they are seen, they're a disturbing take on the 'little green men' image. Do you like jump scares? This movie has one of the best ever accomplished and it involves the aliens.

10 The Thing

The Thing (1982)

The Thing 1982
Universal Pictures

The Thing, directed by John Carpenter is one of the classic extraterrestrial films of the '80s and stars Kurt Russell as a flame-throwing action hero. What makes the creature of this flick so unique is its unpredictability. The Thing could be anyone, and that tension is well played to the audience.

Those moments when it does show itself, in one form or another, are gleefully disgusting, as the creature causes mayhem through gruesome practical effects and off-the-wall action sequences. Carpenter controls his scenes with confidence, leaving most of them in silence and letting the audience just be in a tense moment with the characters. This 1983 science fiction film continues to inspire filmmakers to this day.

9 Heptapods

Arrival (2016)

Arrival scientist symbols
Paramount Pictures

Denis Villeneuve has created a wide range of complex films that spark theories and interpretations. However, Arrival is a slow-burning psychological thriller with jaw-dropping visuals (especially of the aliens) and hypnotizing sound effects. This film explores the dynamic between two worlds (ours and those from above), and how a universal system of communication can establish potential relationships.

Amy Adams brilliantly portrays the linguist who attempts to talk to the tripods from outer space. Through symbols and subtitles for the audience, the aliens reveal their intentions in a shocking twist of an ending that begs explanation on numerous platforms. The visual effects are superb and the unique design of the extraterrestrials (who may or may not be threatening, but are pretty terrifying and seem capable of some awful things) give this film a deserving critical and audience appeal.

Related: The Most Underrated Movies About Aliens, Ranked

8 Blue Aliens

They Live (1988)

They Live alien john carpenter
Universal Pictures / Carolco Pictures

They Live is one of John Carpenter’s hidden gems. It uses its premise as a science fiction alien film that contains some sort of social commentary. Former WWE star Roddy Piper kicks ass alongside Keith David in this action-packed, wryly sarcastic thriller about the dangers of commercialism.

As these characters see the world hidden before their very eyes, the beings that lurk among the masses are revealed. The freakishly looking aliens are not only practical effects-based but also unnerving, with seemingly skinless faces and bulging eyes. This film is a staple of '80s cinema that continues to hold up decades later.

7 Yautja

Predator (1987)

Predator monster
20th Century Fox

When the creature removes its helmet, audiences can all agree with Major Dutch Schaefer (Arnold Schwarzenegger) that the Predator is one ugly mother… we don’t need to add the rest. The sheer strength of this creature is enough to send chills down the spines of anyone unlucky enough to cross its path.

What director ​​John McTiernan adds to the science fiction genre is allowing the audience to see the point of view of the extraterrestrial. The POV shots through the eyes of the predator allow us to get a closer look at how it interacts with the world around it. The Predatorfranchise has been revamped and continued since its 1987 debut, which goes to show its immense success and popularity, and just how iconic that dreadlocked and dread-inducing alien is.

6 Klowns

Killer Klowns From Outer Space (1988)

killer klowns from outer space chiodo brothers
Trans World Entertainment

The sheer combination of bizarre and unnerving visuals, mixed with the generalized preconception of clowns as creepy, makes Killer Klowns From Outer Space a gem for cult horror fans. The film is by no means a critical success. However, it has garnered an enormous following which sparked Universal Studios Halloween Horror Nights to feature its own haunt.

The extraterrestrials were created with practical and unsettling effects, creating different variations of clowns and exaggerating their features in horrifying, disturbing ways. While it may not be a film that takes itself seriously, and putting aliens and clowns together is an unusual choice, it brings together two of our most common fears. It has surely paid off and the film’s success is felt over thirty years later. These are some of the weirdest, funniest, creepiest, and most bonkers extraterrestrials ever put on film.

5 The Blob

The Blob (1958)

The Blob 1988
TriStar Pictures

Just like one of our greatest dilemmas in horror is being afraid of that which we cannot see, something similar works for threats that don't have a specific shape. The Thing was a great example put above. And in The Blob, the point is definitely set in stone. Sure, the Steve McQueen-led classic of the '50s showed it first, but in the 1988 remake, the bets were off.

Directed by Chuck Russell, The Blob told the same story of an alien invading a small town and young people leading the battle in trying to fight it. The problem is there's no monster. At least, not a usual one. This time the menace is a giant blob of lethal jelly that can swallow you whole and eat every molecule of your body. The special effects are still impressive to this day.

4 "Jean Jacket"

Nope (2022)

Nope Jean Jacket
Universal Pictures

The monster in Jordan Peele's Nope is beautiful, deadly, and poetic. It's a massive shape that sometimes represents a spaceship, other times a vessel, and other times just the alien. There's no way to explain it because it keeps evolving with the plot about a group of people trying to document the existence of a flying saucer that's eating up people.

The flying saucer is revealed to be an alien being that gets nicknamed Jean Jacket. However, a science consultant during writing actually named the alien Occulonimbus edoequus, which means “hidden dark cloud stallion eater.” Once you understand the visuals presented during the introduction of the film, you will get goosebumps. If there ever was a reason for having a blood rain take place on the screen, this movie's it. Nope is an amazing piece of genre cinema.

Related: These Are Some of the Best Special Effects in Horror

3 Eve

Species (1995)

species film natasha
MGM/UA Distribution Co.

We were not going to forget the mid-'90s extravaganza of horny horror, Species. Starring newcomer Natasha Henstridge, the film tells the story of a government experiment gone wrong: when receiving DNA from space, scientists follow the advice of extraterrestrial beings and combine the strand with that of a human.

The result is a beautiful killing machine named Eve that seduces men and is always hungry for eating their whole bodies. Special effects are pretty good and considering it sparked a couple of sequels, this is a '90s film that seemingly holds up.

2 Martian Invaders

War of the Worlds (2005)

War of the worlds alien
Paramount Pictures

In Spielberg's take on the H.G. Wells tale, War of the Worlds, the aliens are huge tripods that have been hiding underground for many years. When they wake up, they emerge from the Earth causing massive earthquakes. But this is not the worst thing.

They're actually hungry and violent, and right off the start, they begin blasting people into pure ash, and sometimes eating them up. If you don't think they can be scary, just wait for the ferry scene and we'll talk.

1 "Clover"

Cloverfield (2008)

Cloverfield alien monster
Paramount Pictures

Found footage sci-fi horror film Cloverfield is a modern genre classic that sadly didn't have the proper sequel it deserved (at least for now). Yes, 10 Cloverfield Lane is seemingly part of the universe but all we wanted was to see its huge monster again.

In Cloverfield, New York City is ravaged by a creature so massive our weapons system doesn't hurt it and only makes it angrier. When we see it up close, in one of the main character's death scenes, we can't help but imagine the terror of facing death in the face.