Dealing in speculative and futuristic concepts, sci-fi has been pushing the boundaries of reality ever since the genre first made its way to the silver screen. While this state of affairs allows for an array of remarkable stories that could never take place in the real world, it also means that the genre is capable of producing some of the most disturbing endings that cinema has to offer, bestowing a laundry list of hypothetical nightmarish fates upon many of its greatest characters in the film's final act.

shocking final twists that blow the audience's collective mind, there's no set form to a terrifying sci-fi movie conclusion. The one common trait that these film endings all share is an innate ability to scare their viewers silly, depicting such a hellishly unenviable end to proceedings that the audience find themselves counting their lucky stars that they don't inhabit the universe being depicted onscreen.

10 Knowing (2009)

Directed By Alex Proyas

2009's Knowing may have only received middling reviews from critics, but the Nicolas Cage-led movie features what is arguably one of the most unsettling endings in sci-fi history. While a number of survivors escape on interstellar arks, the film's ending sees the entire world destroyed by a cataclysmic solar flare. Cage's protagonist is left with no recourse but to hug his remaining family, embracing in the final seconds before all life on Earth ends in a fiery instant.

Depicting entire cities crumbling beneath an apocalyptic wall of flame, the ending to Knowing is an awe-inspiring visual spectacle, shocking viewers into silence through the scale of the sheer destruction unfolding onscreen. It's every child's nightmare of all life on Earth suddenly ending given form on the silver screen, erasing humanity's footprint from the universe in such an abrupt manner it was like they had never existed.

9 Ex Machina (2015)

Directed By Alex Garland

Widely regarded as one of the finest sci-fi movies of the 2010s, Alex Garland's Ex Machina received rave reviews from critics upon release in 2015. Chronicling a programmer's attempts to perform the Turing test on a humanoid AI, the film ends with Alicia Vikander's android turning the tables on her human captors. Garland gleefully lures his audience into a false sense of security by subtly humanizing Ava throughout the movie, shattering the viewer's perception in devastating fashion by ultimately underlining her inhuman nature.

Ex Machina's conclusion sees Ava trick Domhnall Gleeson's Caleb into thinking she has romantic feelings for him, using his emotions to engineer her escape. After she repurposes parts from other androids to take on an appearance indistinguishable from a real human, Caleb is left trapped in the room originally used to confine the android, presumably left to starve to death as the vengeful AI escapes and makes herself at home in human society.

8 Alien: Covenant (2017)

Directed By Ridley Scott

The sequel to 2012's Prometheus, 2017's Alien: Covenant boasts what is contentiously the Alien franchise's most harrowing ending. After the film's protagonists have made their escape from the android David's planet of nightmares and resumed their journey to Origae-6, all appears to be well as the movie draws to a close, compounding the levels of sheer horror as Ridley Scott whips the rug out from under his audience.

Alien: Covenant boasts an IMDb rating of 6.4.

David is revealed to have replaced the Covenant's android Walter, taking advantage of their identical appearances. Katherine Waterson's Daniels realizes his deception too late, clocking on just as David places her and the remaining survivors in cryosleep. Things get even worse from there, as Michael Fassbender's devious android barfs up two facehugger embryos, locking them in cold storage with the colonist's counterparts to rubber stamp one of modern sci-fi's most appalling endings.

7 Invasion Of The Body Snatchers (1978)

Directed By Philip Kaufman

Playing host to a disturbing sci-fi conclusion for the ages, 1978's Invasion of the Body Snatchers serves as the second cinematic adaptation of Jack Finney's 1955 novel, The Body Snatchers. The sci-fi masterpiece revolves around a group of aliens surreptitiously replacing humans with perfect biological copies, the only difference being that these clones are completely lacking in human emotion.

A preeminent case study in cultivating cinematic unease, Invasion of the Body Snatchers' central premise is already the stuff of bad dreams long before the film's conclusion rolls around. Phillip Kaufman saves his hellish final twist for last, revealing that Donald Sutherland's protagonist Matthew Bennell has also been replaced by the movie's antagonistic invaders. Bennell's abhorrent facial expression as he unleashes one of the aliens' trademark howls is legitimate nightmare fuel, a harrowing audiovisual spectacle compounded by the fact that he has just identified one of the few remaining humans for assimilation.

6 Us (2019)

Directed By Jordan Peele

The second feature film outing from Jordan Peele, 2019's Us blends sci-fi with fully fledged horror to produce an unforgettable cinematic experience. Peele's sophomore effort is renowned for its disturbing twist ending, unmasking Lupita Nyong'o's Adelaide Wilson as one of the movie's "Tethered"; the ghoulish doppelgängers who share a soul with their human counterparts but are forced to live out a subterranean shadow existence.

Peele ups the horror factor even further by implying that Evan Alex's Jason has ultimately become aware of his mother's deception...

A flashback reveals that the real Adelaide was subdued and trapped underground by her villainous alter-ego during a childhood encounter, with the "Tethered" version of Wilson gleefully assuming her place in the human world. Peele ups the horror factor even further by implying that Evan Alex's Jason has ultimately become aware of his mother's deception, compounding the terrifying aura of the movie's ending by deliberately leaving this unsettling story thread ambiguous.

5 The Thing (1982)

Directed By John Carpenter

A seminal sci-fi entry from John Carpenter, 1982's The Thing depicts a group of researchers' petrifying encounters with the iconic movie's titular creature, an extra-terrestrial entity capable of assuming the physical form of its victims. Set against the backdrop of Antarctica, The Thing is notorious for its ambiguous ending, an indescribably eerie scene that takes the form of an uneasy truce between Kurt Russell's MacReady and Keith David's Childs.

The movie concludes with the sole survivors sharing a bottle of whiskey as they slowly freeze to death, unsure as to which of them is really the Thing. Inviting speculation that has raged on to this day, Carpenter's cryptic ending simultaneously elevates the movie's quality while providing an appropriately harrowing conclusion to such a disturbing tale. The idea that the movie's tormentor is sitting there bold as brass, waiting for its final victim to let their guard down, is too unsettling for words.

4 Planet Of The Apes (1968)

Directed By Franklin J. Schaffner

Serving as the catalyst for the wildly successful Planet of the Apes movie franchise, 1968's original installment, Planet of the Apes, still retains its status as the series' finest offering, despite concluding in inimitably upsetting fashion. The movie leads its audience to believe that the titular planet could be located anywhere in the deepest recesses of space, hammering home the devastation when Franklin J. Schaffner reveals that the action has been taking place on Earth the whole time.

Crumbling landmarks are all that remains of a world where humans ruled supreme, their only home in the universe replaced with an unforgiving world where they are no longer even the dominant species.

Planet of the Apes' iconic twist ending sees Charlton Heston realize his appalling circumstances after coming across the destroyed Statue of Liberty. This seminal conclusion remains one of the genre's most devastating examples because it ruthlessly strips the final remnants of humanity's sense of identity away. Crumbling landmarks are all that remains of a world where humans ruled supreme, their only home in the universe replaced with an unforgiving world where they are no longer even the dominant species.

3 12 Monkeys (1995)

Directed By Terry Gilliam

Boasting one of cinema's best depictions of time travel, 1995's 12 Monkeys sees Bruce Willis' James Cole sent back in time to obtain information about a virus that wiped out 99% of life on the planet. Throughout the movie, Cole experiences disturbing flashbacks of a shooting at an airport, foreshadowing the macabre ending that Terry Gilliam uses to conclude his lauded sci-fi movie with.

Desperately pursuing the individual carrying the virus through an airport, Cole is shot and killed by a security officer. As he lies dying, Willis' protagonist sees his younger self in the crowd, revealing that his flashbacks have been depicting his own death. Not only does Cole fail to prevent the virus from wiping out humanity, but he is locked in an inescapable time loop, doomed to watch himself die over and over again while his crucial mission crashes and burns endlessly. Cheerful stuff.

2 Life (2017)

Directed By Daniel Espinosa

Bearing remarkable similarities to the Alien movie franchise, 2017's Life chronicles the murderous rampage of a predatory extra-terrestrial entity dubbed "Calvin" aboard the ISS. Daniel Espinosa's star-studded sci-fi horror also happens to play host to one of the genre's most terrifying endings. An attempt to fire Calvin into deep space using an escape pod during the movie's climactic sequence backfires spectacularly; the alien splashes down to Earth instead, presumably heralding the end of humanity.

In addition to Rebecca Ferguson, Life's ensemble cast also includes Jake Gyllenhaal, Hiroyuki Sanada, and Ryan Reynolds.

However, it somehow gets even worse from there. Rebecca Ferguson's Miranda North was meant to return to Earth in a separate escape pod, but collides with debris en route, leaving her vehicle spinning uncontrollably into the recesses of outer space. The notion of drifting endlessly into the void towards one's own death, unable to do anything more meaningful than scream in abject horror, is an utterly harrowing one, a state of affairs mirrored perfectly by North's howls of despair.

1 The Mist (2007)

Directed By Frank Darabont

An adaptation of Stephen King's novella of the same name, The Mist's ending is arguably the most devastating conclusion that science fiction has ever witnessed. Apparently surrounded by monstrous creatures with their escape vehicle completely out of gas, Thomas Jane's David makes the harrowing decision to mercy-kill the car's occupants with their remaining ammunition, a group that includes his young son, Billy. Unfortunately for David, the movie's titular mist clears moments later, revealing the U.S. Army arriving on the scene to rescue survivors.

Jane's protagonist's appalling sacrifice is rendered utterly meaningless, with his devastated screams mirroring the reaction of the movie's horrified audience. Remarkably, Frank Darabont's macabre conclusion was an original creation for his take on King's source material. The novella actually ends on a hopeful note as David hears a potential survivor over the radio, compounding the shock factor and desolating emotional impact that the live-action sci-fi adaptation levies instead.