Of course, most twist villains exist prior in their reveal as supporting characters, totally unsuspected of being the driving force of conflict within a film until they're dramatically revealed. Even in movies that specifically have a murder mystery or otherwise mysterious villain whose identity needs uncovering, good twist reveals will eventually place the blame on a character no one suspects.
10
Norman Bates
Psycho
Often considered to be the original slasher movie, Alfred Hitchcock's Psycho has left a massive crater of cinematic influence even so many years later. Today, most people recognize Norman Bates as the true evil behind the film's atrocities through sheer pop culture osmosis, if nothing else, with entire series like Bates Motel dedicated to his psychopathy. It's easy to forget that in the original narrative, the reveal that Norman was the murderer all along is presented as a huge shock.
Every piece of evidence points to the matriarch proprietor of the Bates Motel as the culprit, especially when the silhouette of an old woman is shown raising a knife for a split-second in the infamous shower scene. However, the ultimate twist that Norman himself has the murderer, having killed and impersonated his mother many years ago, is a terrifying one indeed to the uninitiated. The first shot of him wearing his mother's clothes and wig is horrifically jarring, and his insidious grin the film closes on as he sits in captivity lingers as a chilling final image.
9
Billy And Stu
Scream
While Psycho may have more or less established the slasher movie as a popular horror subgenre worthy of imitation, Scream was the first film to examine the arbitrary rules these stories had begun to follow and turn them on their head. The identity of the Ghostface killer is a huge crux of the film's action, and the story absolutely demolishes typical expectations with the reveal that Ghostface is not just a single lone actor, but a pair of murderers working in tandem. The mechanics as to how Scream pulls this off is quite impressive.
Protagonist Sidney at first seems to have the perfect candidate for the killer's identity with her mother's supposed murderer. Her boyfriend, Billy, does admittedly draw some suspicion, but the timing of his appearances alongside Ghostface's activities seem to make him an impossible choice. The ultimate revelation that Billy is working in tandem with the comic relief character Stu is a clever way to subvert expectations. After all, why wouldn't a masked murderer have an accomplice?
8
Mr. Waternoose
Monsters, Inc.
Over the years, Pixar has tried out many villains with twist identities, such as Bellwether from Zootopia or Screenslaver from Incredibles 2. Sadly, most of these twist villains end up lacking impact due to a combination of their evil plans making little sense or their reveals being far too obvious. But one of the company's first attempts at the concept, Mr. Waternoose from Monsters, Inc., is still one of their most effective.
Mr. Waternoose is so shocking as a twist villain because the film already has an antagonist with Randall, though in retrospect, it seems obvious that he wouldn't be acting alone. Waternoose plainly tells Sully that he'd do anything to keep the company alive early in the film, and his design goes from friendly mentor figure to terrifying spider monster in a split second when his true intentions are finally uncovered. A callous CEO who puts the fate of his company above all else, Mr. Waternoose is one of the more unnerving villains Pixar has dreamed up.
7
Keyser Söze
The Usual Suspects
The Usual Suspects is a decent crime thriller that's elevated into cult status off of the sheer power of its twist villain's reveal. The entire mystery of the film hinges on the hunt for the legendary criminal Keyser Söze, who is feared as an almost mythical force in the criminal underworld by police and crooks alike. The film is told via flashback with the interrogation of a survivor of Söze's latest attack used as a framing device.
The interview eventually ends, and con artist Verbal is eventually released. It's only after he gets away that Agent Dave Kujan looks around his borrowed office and realizes that every detail of Verbal's story was completely made up, improvised using various words around the room as inspiration. It turns out that Keyser Söze is none other than Verbal himself, who is able to get away just in the nick of time in a chilling final scene. Few films have pulled off as big of a sucker punch as The Usual Suspects gets away with.
6
John Kramer
Saw
James Wan's original Saw is still a masterpiece of subversion, even if the subsequent Saw sequels haven't quite been able to recapture the magic. The first movie introduces the Jigsaw killer, a sadistic slasher villain who crafts twisted "games" for his victims to play, often forcing them to mutilate themselves in order to survive. For the majority of the film, the mysterious hospital orderly Zep seems to be the primary running lead for Jigsaw's identity.
However, the scene in which the unidentified bald man in the center of the decrepit bathroom stands up as the Saw theme blares eventually proves otherwise. It's unearthed that terminal cancer patient John Kramer is the real menace behind saw, his diagnosis giving him a new appreciation for life that he wants to forcibly instill in his victims. Kramer goes on to become a legendary horror movie villain, but his shocking twist identity reveal is still one of the greatest.
5
Angela/Peter Baker
Sleepaway Camp
When it comes to the discussion of the greatest horror movie twist villains, Peter "Angela" Baker from 1983's Sleepaway Camp is another top contender. The movie follows a lonely young girl named Angela Baker, who exhibits signs of trauma following her brother's death in a tragic accident. Sent to a sleepaway camp for the summer, Angela's bullying becomes a nightmare when a series of grisly murders start plaguing the campgrounds.
In a stunning turn of events, Sleepaway Camp ends with Angela's true identity out in the open. Not only was Angela the killer all along, but she is actually Peter Baker, the surviving child of the accident in which the real Angela died, disguised as his late sister. The blood-curdling final scream and facial expression Peter makes as his secret is exposed is one of the most captivating scenes of any slasher movie, and the film's ability to reveal a villain that was actually the main protagonist all along is devastatingly effective.
4
Mysterio
Spider-Man: Far From Home
Mysterio is an interesting case for a twist villain that must be appreciated in a vacuum. For the most part, the Marvel Cinematic Universe's villains are glaringly obvious, especially to those who know the comics. But with no prior knowledge of Mysterio as a character, Jake Gyllenhaal's version of a vengeful illusionist hoping to get back at his dead nemesis is a wonderful antagonistic jerk.
At first, even comic readers might be hopeful that the MCU's version of Mysterio is a good guy after all, helping to defeat the threat of the Elementals and guide Peter Parker in lieu of Tony Stark's mentorship. But the moment in which Quentin Beck breaks character and laughs to his team about tricking Parker into handing over the valuable E.D.I.T.H. technology. With charisma to spare, Beck's ultimate betrayal and lasting stab at Spider-Man by revealing his secret identity to the world makes him a fantastic twist villain.
3
Ransom Drysdale
Knives Out
It's easy to see why Knives Out inspired a whole spin-off series based on Daniel Craig's effete detective Benoit Blanc, being such a fun murder mystery with a genuinely unexpected villain. The star-studded cast play a family of spoiled rich scions who are left in shock when their father is suddenly killed via slit throat. Grandson Ransom Drysdale hires the famous private investigator Benoit Blanc to uncover the truth - Patriarch Harlan Thrombey took his own life after being mistakenly killed by his beloved live-in nurse, Marta.
With Harlan killed by a seemingly innocent mistake and the plot being driven by Marta's attempts to avoid prosecution, it doesn't seem as though Knives Out even has an overarching villain. This notion is disproven, however, when its stunningly unveiled that Chris Evans' Ransom purposefully poisoned Harlan in order to implicate Marta and prevent her from inheriting his estate. Chris Evans nails it as a smug villain bold enough to hire the world's best detective to investigate his own crime, and his unflinching smile and curt laugh upon being caught are pure gold.
2
Mr. Glass
Unbreakable
Considering M. Night Shyamalan's many twist endings, it figures that the famed director would come up with one of the better twist villains to ever exist in a movie. At first, Unbreakable presents itself as a relatively straightforward supernatural thriller, telling the story of Bruce Willis' David Dunn, who learns he has superpowers after being the sole survivor of a deadly train crash. After coming to the realization, Dunn enlists the help of zealous comic book reader and brittle bone disease sufferer Elijah Price to make sense of his new place in the world.
As great as Elijah's advice is, Dunn soon realizes that he is a domestic terrorist who had a hand in creating the very same train accident David was in. Calling himself Mr. Glass, Elijah sees himself as a mastermind villain from a comic book meant to act as David's archnemesis. Samuel L. Jackson lends the villain a certain vile tenderness that's hard to find anywhere else, making for an unforgettably surprising antagonist.
1
Scrappy-Doo
Scooby-Doo
Villainous plot twists don't always have to be stunningly dramatic reveals that shock audiences into submission. In many cases, they're at their best when played for laughs, as demonstrated by James Gunn's live-action Scooby-Doo film. The movie begins with the classic Scooby-Doo gang split up due to personal differences, only to be brought back together by an eccentric resort owner named Mondavarious. Soon, the gang uncover a ghoulish plot to release actual real demons via an ancient ritual led by Mondavarious himself.
Mondavarious ends up being a humanoid robot controlled by none other than Scrappy-Doo, the much-maligned and unpopular nephew of Scooby who acted as a sidekick before being kicked out of the gang for his gross behavior. The entire plot ends up being a ruse orchestrated by Scrappy to get his revenge on the gang, making for a hilariously unexpected twist villain. Even if Scrappy isn't set-up earlier in the plot, anyone more than vaguely aware of Scooby-Doo in pop culture will remember him as a deep cut that works perfectly as a scorned movie antagonist.