Filmmakers love to throw curveballs at audiences to surprise them and keep them on the edge of their seat, for some directors (M. Night Shyamalan) it was expected from their films.
So the most curved of balls is to build up a character from the start of the film, only to bump them off before we've even got stuck into the plot.
Here are nine examples of 'decoy protagonists' - those main characters whose screentime was tragically cut short.
Of course, there are major spoilers in this article.
Marion Crane - Psycho
The original and most famous 'decoy protagonist' was created by Alfred Hitchcock.
Through the first half of Psycho, Marion Crane takes the majority of the screen time - she steals $40,000 from her boss and takes off to give it to her boyfriend in another State; along the way she is questioned by a state patrol officer after falling asleep at the wheel, and then trades in her car and before stopping to stay the night in the ill-fated Bates Motel.
Once Marion is slaughtered in the shower by 'mother', the story then flips to Marion's sister Lila and fiancé Sam as they investigate what happened to the late Marion Crane.
Alfred Hitchcock asked cinemas for a "no late admission" policy because he thought that latecomers would feel cheated if they didn't see star actress Janet Leigh.
Leigh's agent advised the star against taking the role due to how quickly she would exit the film, to which Leigh replied: "Ah, but who are they talking about the rest of the film?"
Joe Brody - Godzilla (2014)
Going into the latest Godzilla movie, Bryan Cranston had just finished Breaking Bad and was one of the biggest stars in the world, all of the film's marketing and trailers focused on him.
It then came as a surprise to viewers when Cranston's character Joe Brody is killed within the first third of the movie.
Nuclear physicist Joe and his son Ford visit a power plant that was destroyed fifteen years earlier to find out what caused the destruction, only for a large winged creature to emerge from a chrysalis and tear down the walkway that Joe is standing on, mortally wounding him.
After the film was released, Bryan Cranston admitted he thought that killing off his character so early was a' narrative mistake', explaining "I told them that even if I wasn’t doing this role, that character shouldn’t die at that point. It’s just bad narrative, but they were too far down the road".
Casey Becker - Scream
Another famous example is Drew Barrymore's (brief) appearance in Scream, one of the slasher movie's biggest stars, who is killed off by the masked murderer within the first ten minutes.
Barrymore's character Casey gets taunted over the phone by Ghostface, who shows Casey her boyfriend tied and gagged in a chair outside; the killer then chases her, and as Casey struggles, he stabs her multiple times and leaves her hanging from a tree for her parents to find.
When Barrymore heard about Scream, she approached the production team and asked for a role, they duly obliged and offered her the lead role of Sidney Prescott.
Before filming began, unexpected commitments meant Barrymore could play the demanding lead role and instead offered to play Casey.
Barrymore was marketed as one of the film's main characters and it took audiences completely by surprise when she was killed off before the film had even warmed up.
The production team considered killing off the actress as a calculated risk, reasoning that the death would be so shocking and unexpected that audiences would believe anyone could die at any time.
Lucius Hunt - The Village
M. Night Shyamalan's psychological thriller - set in a 19th-century village terrorised by creatures from surrounding woods - saw the film follow Lucius Hunt, the shy, quiet young man who wants to pass through the woods to bring back medicines.
While he continues to request to pass find life-saving medicines, he is repeatedly and frustratingly rebuffed by the village's 'Elders'.
When Lucius and Ivy, the blind daughter of the village's chief Elder, arrange to get married, Lucius is suddenly stabbed by a mentally unstable villager who is also in love with Ivy; and while Lucius lives to the film's end, he spends the rest of the film bedbound, while the focus shifts to Ivy.
While Shyamalan's mind-bending tale was criticised for having too many unnecessary twists and a disappointing climax, Lucius' stabbing halfway through the film is unexpected and was the only genuinely exciting surprise in the underwhelming story.
Dallas and Kane - Alien
Ridley Scott's sci-fi horror masterpiece threw up surprises as well as scares, as the top-billed stars were killed off earlier than expected.
John Hurt - the most established actor in the cast list - who played Kane, was the first to fall victim to the alien in the iconic Chest Buster scene, which would have thrown audiences a real curveball, not expecting one of the top actors to go out in such a fashion.
Meanwhile, Tom Skerritt was given top billing for his character of Dallas - as audiences would assume the actor would be playing the main character - but he is ambushed by the alien about halfway through the film.
At the time, Sigourney Weaver was an unknown actress and no-one would have expected her to be the only survivor, while the film's well-known cast was killed off in reverse order of their credit billing.
Sgt. Thompson - The Hurt Locker
In a similar way to Scream, Iraq war movie The Hurt Locker has the opening scene introduce a character - played by a well-known star - only for them to be killed off before the film properly gets started.
In The Hurt Locker, it is Sgt. Thompson, played by Guy Pierce, whose unsuccessful attempts to remotely defuse an Iraqi bomb force him to don protective gear to do it manually, only for a local to detonate as he is approaching.
The film then kicks off with Jeremy Renner taking over his unit, as Kathryn Bigelow's story of an Iraqi bomb disposal team won six Academy Awards including Best Picture.
Interestingly, as well as Guy Pierce, the film's other biggest-name actor, Ralph Fiennes, also has less than 10 minutes of screen time.
Arlene, Shanna, Julia and Pam - Death Proof
Quentin Tarantino's lowest-rated film saw him introduce the entire cast for the first half of Death Proof, only to unexpectedly kill them off all at once.
The characters Arlene, Shanna, Julia and Pam meet 'Stuntman' Mike at a Texas strip club, Pam (played by Rose McGowan) is then given the focus as it's expected that she'll be the film's protagonist, only for Stuntman Mike to kill her with his 'Death Proof' car, and then run down the rest of the girls.
The second half of the film involves a completely different cast, except for the reappearance of Stuntman Mike, as the film takes place in a completely different area and filmed in a completely different style, making it feel like it is watching the sequel to the first movie while it is still playing.
Tarantino's dedication to the Grindhouse project, and imitating the style of 1970s exploitation double features contributed to the film's unusual feel and overly-edited look; ultimately this resulted in Death Proof to be considered Tarantino's weakest film.
A Nightmare on Elm Street - Tina Gray
The legendary 1984 horror flick introduces Freddie Kruger through Tina Grey's dreams, as audiences believed that it would be Tina that would be the film's protagonist.
Then, during a sleepover, Tina becomes the first member of the group to die, butchered by Freddie while asleep, with her body flying around the room and getting sliced and slashed by Freddie’s' glove.
Before he repeated the trick twenty-two years later on Scream, director Wes Craven killed the supposed main character early on in the film as an homage to Marion Crane in Psycho.
The Godfather - Vito Corleone
Marlon Brando's lasting portrayal as the head of the Corleone crime family is one of the most recognised and greatest onscreen gangsters in film history.
But Don Vito is gunned down less than forty minutes into the film's two hours and 57 minutes runtime, spending the majority of the film lying in a hospital bed.
Vito's son Michael is the film's main character, despite what all the film's marketing and lasting images would suggest, as Vito dies of a heart attack before the film reaches its conclusion.
For playing Vito, the top-billed Marlon Brando won the Best Actor Oscar, despite his character having much less screen time than the true protagonist, played by Al Pacino - who missed out on the Best Supporting Actor for his performance as Michael.