One of the most memorable and influential sci-fi movie scenes ever conceived, Alien’s iconic chestburster sequence has been haunting our nightmares since it first debuted in 1979. The scene depicting a bloody Xenomorph exploding out of John Hurt’s solar plexus for the first time has gone down in the annals of cinematic history as one of the most famous moments ever brought to life onscreen, launching a multi-movie franchise and serving as an inimitable calling card for one of the greatest sci-fi movies of all time.

With that being said, it’s far from the only harrowing moment that the wider genre plays host to. Science fiction is loaded with movie moments that will haunt me forever for one reason or another, from desolating twists that we’ll remember forever to the most terrifying movie endings that the genre has to offer. Certain scenes are seared onto my retinas forever, inviting horrified introspection that continues long after the credits have rolled.

10

Alien (1979)

The Chestburster Sequence

One of the most iconic sequences in cinematic history, Alien’s legendary chestburster scene has lost none of its terrifying aura; a nightmarish spectacle that lingers in the mind long after the movie’s final cut to black. It’s a remarkable feat given that Ridley Scott’s iconic 1979 sci-fi horror movie is rapidly approaching the fiftieth anniversary of its release, but the Xenomorph’s first appearance remains such a uniquely horrifying moment that time has had little effect on the scene’s inimitable shock factor.

The crew’s initial air of panicked confusion, the change in the stricken Kane’s expression from confusion to terror, and the chilling screams and convulsions that follow all serve to ramp up the tension for the sequence’s crowning jewel. Deftly balancing wonder with unabated disgust and horror, the unforgettable instant where the Xenomorph’s squalling head punctures Kane’s chest to introduce popular culture to one of its most iconic antagonists is a moment that will haunt me forever.

9

The Substance (2024)

“Monstro Elisasue”

Earning five Academy Award nominations, Coralie Fargeat’s The Substance sees a career-best Demi Moore and Margaret Qualley combine for one of the most shocking sci-fi horror movies of all time. In addition to The Substance’s numerous horror Easter eggs, Fargeat’s wickedly satirical body horror is loaded with shocking sequences. However, none can rival the movie’s triumphant reveal of its most visually horrifying element; the monstrous amalgamation of its two leading ladies referred to as “Monstro Elisa-Sue.”

After murdering Moore’s Elisabeth Sparkle, Qualley’s Sue makes the fateful decision to attempt to create a new version of herself using leftover activator serum, despite the warnings that the substance is only fit for a single use. The result is a visual that remains imprinted on the viewers’ minds long after the credits roll; Monstro Elisa-Sue, a nightmarish mutated blend of the two women, with disjointed limbs and body parts popping out in random directions and complete with both Elisabeth and Sue’s faces.

8

The Invisible Man (2020)

Adrian Frames Cecilia For Emily’s Murder

A sci-fi horror remake that completely changed the original, 2020’s The Invisible Man added horrifying new elements to a classic story to produce one of the more unsettling viewing experiences in recent memory. From the blood-chilling sight of the movie’s eponymous villain becoming partially visible for the first time to the hair-raising attack on Aldis Hodges’ James in the purported safety of his own home, the movie is loaded with scenes that stick with you.

A nightmarish case in point, the death of Cecilia’s sister Emily is enough to traumatize everyone. Using his trademark suit to hide his approach, Adrian murders Harriet Dyer’s charge before Cee’s horrified eyes, placing the knife in his former partner’s hand to frame her for her own sister’s murder. One of the more desolating moments from the genre in recent memory, Elisabeth Moss’ shell-shocked expression of abject horror is an accurate reflector of my own emotional state after this scene has finished playing out.

7

Signs (2002)

The Alien Is Caught On Camera

This particular sci-fi moment may have lost some of its notoriety as of 2025, but a memorable scene from M. Night Shyamalan’s Signs is still notorious for giving a generation of children nightmares. The cinematic twist master’s sci-fi horror chronicles an alien invasion, with the movie’s most unsettling scene playing out in the form of Joaquin Phoenix’s Merrill watching a news clip from a birthday party in Brazil showing the first sighting of the movie’s alien invaders.

The anchor warns viewers that what they are about to witness will disturb them, and she’s not wrong; as the children’s screams build in intensity, the silhouette of a terrifying alien creature emerges onscreen from a nearby piece of shrubbery, confirming the extraterrestrial’s ability to camouflage. An iconic visual that scared this writer’s generation silly, the scene’s jarring style of reveal is just as terrifying as the narrative development’s connotations for the wider movie. As such, Phoenix’s mask of sheer horror encapsulates the shocking aura of this immortal moment perfectly.

6

Nope (2022)

Jean Jacket Devours The Fair-Goers

The third feature film from acclaimed horror director Jordan Peele, 2022’s Nope saw the director’s furthest departure from his parent genre to date. However, while Nope’s heavy extraterrestrial influences mean that it is unquestionably a sci-fi film, Peele’s latest outing retains enough elements of a fully-fledged horror movie to produce an outing loaded with terrifying scenes that are capable of haunting audiences for years to come.

Chief among said scenes is the reveal of Jean Jacket’s alien nature, a development that regrettably comes at the cost of Jupiter’s Claim’s audience. The theme park’s visitors are inhaled by the predatory extraterrestrial before the camera cuts to the appalling sight of howling humans beginning to be digested alive, dropping the bombshell that Nope’s antagonist is an alien rather than a flying saucer in blood-curdling fashion. The claustrophobic visuals of Jean Jacket’s dinner lodged in its digestive tract are harrowing, but the screams of the dying that subsequently echo on for hours are straight-up nightmare fuel.

5

Invasion Of The Body Snatchers (1978)

Matthew’s Scream

Jack Finney’s 1955 novel The Body Snatchers has been adapted for the screen on no less than four separate occasions, with 1978’s acclaimed sci-fi horror entry Invasion of the Body Snatchers widely regarded as the best Body Snatchers movie. The film is notorious for its unsettling twist ending, a macabre development that reveals Donald Sutherland’s Matthew Bennell has been duplicated by the movie’s aliens.

Blissfully unaware that the aliens have gotten to Sutherland’s charge, Veronica Bellicec’s Nancy approaches Matthew with a smile on her face, only for her expression to dissolve into unabated horror in short order. Producing the duplicates’ signature high-pitched scream, Bennell points an accusatory finger at the despairing Nancy. As his face freezes into a grotesque howling mask, the camera centers in on his gaping maw to conclude a scene that has been haunting our dreams since 1978.

4

Life (2017)

The Pod Is Opened

A star-studded sci-fi horror from Daniel Espinosa centered on a murderous extraterrestrial enтιтy dubbed “Calvin,” 2017’s Life boasts one of the most terrifying sci-fi movie endings of all time. A failed attempt to launch Calvin into outer space sees the ISS’ two remaining space pods swap courses after colliding with debris. Rebecca Ferguson’s Miranda North is left to scream despairingly into the void, confronted with the reality of her own death after the collision causes her pod to hurtle into deep space unchecked.

However, the flip side of Life’s twist ending is even more desolating. Jake Gyllenhaal’s David Jordan made the ultimate sacrifice to save the world, only to see his tormentor plummet to Earth with him anyway in the cruelest twist of fate imaginable. Despite his desperate pleas to keep the alien contained, the fishermen who discover his escape pod open it anyway, unleashing Calvin on the world and presumably heralding the end of humanity.

3

A Quiet Place (2018)

Beau’s Death

A visionary horror franchise from John Krasinski, the A Quiet Place movies depict a world overrun by formidable predatory extraterrestrials. Entirely blind but possessing preternatural hearing, the aliens overrun the world in short order, leaving humanity’s survivors to scratch out whatever silent existence they still can. The original installment sees Krasinski introduce us to this status quo in an utterly devastating fashion, highlighting the new world order through the horrifying demise of his character Lee’s youngest son, Beau.

Innocently activating a battery-powered toy that emanates a loud noise, Beau is set upon and ruthlessly killed by one of the aliens in the movie’s introduction. The young boy is whipped out from under the very nose of his horrified father, just before he can reach him in time. A parent’s worst nightmare brought to life onscreen, the brutal finality with which Beau is torn away in a horrifying instant, and the desolated look in Lee’s eyes as he realizes his son is gone forever make for unforgettably harrowing viewing.

2

The Thing (1982)

The Defibrillation Scene

Following the plight of a group of researchers in Antarctica as they are set upon by a predatory enтιтy capable of ᴀssuming its prey’s physical form, John Carpenter’s The Thing retains its status as one of the most iconic and influential sci-fi horror movies of all time, more than four decades after it was initially released. This wouldn’t have been possible without an array of disturbing scenes for the ages, from the creature attacking the station’s sled dogs to the infamous “blood test.”

With that being said, an iconic Carpenter movie moment stands out from the pack in terrifying fashion. Notorious for some of the most appallingly spectacular practical effects in cinematic history, the sequence depicting Dr. Copper trying to defibrillate Norris has lost none of the shock factor that led to it attaining classic status. Attempting to revive his stricken patient, Copper is caught off guard as Norris’ torso suddenly transforms into a gaping maw, biting his arms off before morphing into the Thing’s latest nightmarish form in the most gruesome way.

1

Annihilation (2018)

The Mutant Bear

A mind-bending tale from Alex Garland, 2018’s Annihilation may have posed more questions than it ultimately answered, but is still widely regarded as one of the best sci-fi horror outings in recent memory. A smorgasbord of unsettling visuals, the film plays host to one of the most disturbing scenes in modern movie history, a sequence that comes about as the unholy result of the Shimmer’s effect on wildlife and vegetation.

The sequence in question sees our heroes come face-to-face with the mutant bear from Annihilation that had previously killed Gina Rodriguez’s Cᴀss. An abhorrent amalgamation of human and bear skulls, this hellish visage becomes even more horrifying by echoing their departed friend’s dying cries instead of normal animal sounds. One of the most disturbing renditions of a monster ever brought to life onscreen, Annihilation’s mutant bear stands as one of sci-fi‘s most prevalent examples of sheer nightmare fuel.