The Spoiler: Little could Ridley Scott have imagined that, one day, John Hurt would reprise his role as Kane in Spaceballs , only for a chestburster to emerge wearing a straw boater and singing "Hello Ma Baby."
Why It Was Unbelievable: For kids too young to have seen Alien, this was their introduction to the life cycle of the xenomorph.
Star Trek Into Darkness (2013)
The Spoiler: In fairness, the marketing for Star Trek Into Darkness went out of its way to hide the real identity of Benedict Cumberbatch's villain. Yet it was exactly difficult to guess, given that J.J. Abrams had publically mooted the return of Khan as long ago as 2009 when he said, "Certain people are destined to cross paths and come together, and Khan is out there ... even if he doesn't have the same issues."
Why It Was Unbelievable: There was no need to make Khan's presence a secret. Since Kirk and co. hadn't meet the guy in Abrams' rebooted Trek universe, the only people Khan was hiding his identity from were the fans.
The Impossible (2012)
The Spoiler: The Spanish poster for Lo Impossible clearly showcased the bruised, battered but reunited Bennett family, rather robbing their post-tsunami plight of much of its dramatic tension.
Why It Was Unbelievable: Other poster campaigns maintained the film's dramatic split between two family groups, so why not this one? The issue was made worse because Spain was the homeland of both the film's director, J.A. Bayona, and the real-life family on which the characters were based.
Citizen Kane (1941)
The Spoiler: As revealed in Family Guy episode 'Screwed The Pooch,' Peter Griffin taped over a rental VHS tape of the Orson Welles classic to announce "it's his sled, it was a sled from when he was a kid. There, I just saved you two long, boobless hours."
Why It Was Unbelievable: Seventy years on, there should be any shock value in giving away one of cinema's most cherished twists - but it's the way that Peter does it that is so scandalous.
Star Wars Episode 1: The Phantom Menace (1999)
The Spoiler: Two weeks before the release of the much-anticipated prequel, John Williams' soundtrack arrived in shops with some telltale track titles. Take track #15, 'Qui Jon's Noble End' - whatever could it mean?
Why It Was Unbelievable: It's not as if the titles had to bear such Ronseal functionality. What's wrong with having a bit of poetry?
The Spoiler: Pity cinemagoers in Portugal, who showed up to watch O homem que matou a própria mãe - which translates as The Man Who Killed His Mother .
Why It Was Unbelievable: In America, Alfred Hitchcock demanded that cinemas not let in anybody once the film had begun. He should've gone to Lisbon to sort the Portuguese out.
The Spoiler: On the one hand - "let's remake Carrie for a young audience who doesn't know what happens." On the other - "let's market it as if everybody has read the book and seen the De Palma film by focusing on the blood-splattered finale."
Why It Was Unbelievable: Amazingly, the 1976 film's trailer was just as spoilerific.
The Lord Of The Rings: The Two Towers (2002)
The Spoiler: Even considering that the 'twist' had existed in print for nearly half a century, it was rather unsporting of the trailer to reveal that the White Wizard was Gandalf, hitherto thought lost down the Mines of Moria.
Why It Was Unbelievable: The fact that Peter Jackson went so far as to open the film with a reminder of Gandalf's apparent death shows that he was aiming for a big dramatic reveal mid-film.
The Spoiler: How much could anybody hate Liam Neeson's new plane-bound thriller? A lot, if you're right-wing pundit Glenn Beck, who used his radio show earlier this year to literally spell out the film's plot to listeners because he was so incensed by the identity of its lead villain.
Why It Was Unbelievable: Non-stop? Fortunately, there's an off switch for Beck's mean-spirited rant.
The Wizard Of Oz (1939)
The Spoiler: Nothing specific here. Just the fact that everybody (and we mean everybody: Muppets, Simpsons, Michael Jackson) has homaged or parodied the classic MGM adaptation that it's possible to know the entire film off by heart without having actually seen it.
Why It Was Unbelievable: Every time you think pop culture has run out of ways to 'do' The Wizard Of Oz , along comes another joke about flying monkeys.
The Crying Game (1992)
The Spoiler: In The Simpsons episode 'Marge In Chains', Mayor Quimby shows how tone-deaf he is to his electorate by revealing in the speech that, "in other news, the chick in The Crying Game is really a man."
Why It Was Unbelievable: The episode was first broadcast on 6th May 1993, less than eight months after the film's premiere and before its home video release. Give people a chance to watch the damn thing, Quimby.
The Crying Game (1992) again
The Spoiler: Mayor Quimby can be forgiven, because the biggest spoiler relating to Dil's big twist was the inevitable side-effect of Jaye Davidson's eye-opening performance. When the Academy nominated him, it had no choice but to place him in the Best Supporting Actor category and give the game away.
Why It Was Unbelievable: Only a few years later, the Academy nominated the fictional Roderick Jaynes for 'his' editing of Fargo , so they should have had the courage to put Davidson into the Actress category to preserve the surprise.
Ender's Game (2013)
The Spoiler: Ender thinks he's competing in a simulation before being told his fighting skills were deployed in an actual life-or-death battle. Clearly, Ender hadn't seen the film's poster, whose tagline gave away the twist that "This is not a game."
Why It Was Unbelievable: It's not exactly difficult to allude to the plot without revealing it; they could have gone for something like "The stakes are higher than you think."
The Incredible Hulk (2008)
The Spoiler: The cameo by Robert Downey, Jr as Tony Stark was meant to be a treat for the faithful fans who stayed to the end of the credits. That was, until the boys from the marketing department discovered its existence and slapped it in the trailer.
Why It Was Unbelievable: Amazingly, Marvel hadn't figured out the 'buzz' that its post-credit stingers generated in the comic book community.
The Thing (1982)
The Spoiler: Do you speak Norwegian? If so, then the plot of John Carpenter's sci-fi thriller is explained during the opening sequence, as one of the Norwegians helpfully shouts in his native tongue, "Get the hell outta there. That's not a dog, it's some sort of thing! It's imitating a dog, it isn't real! Get away, you idiots!"
Why It Was Unbelievable: It's actually kinda funny once you know, reinforcing the haplessness of the soon-to-be-plagued Americans.
The Spoiler: Sometimes, the last thing you want is for a film to be successful. Having gone to all the trouble of keeping Kevin Spacey's name out of the film's marketing, it must have been galling to David Fincher when the MTV Movie Awards awarded the actor as Best Villain.
Why It Was Unbelievable: They give out awards for villainy now?
Arlington Road (1998)
The Spoiler: Any film so predicated on a simple yes-or-no question ("Is Tim Robbins a terrorist?") should really try not to provide an answer in the trailer ("Yes, he is.")
Why It Was Unbelievable: The trailer was so on-the-nose that it's likely many people went in expecting there to be a last-minute twist that Robbins was innocent. Alas, no…
Oz The Great and Powerful (2013)
The Spoiler: A promotional mug gave away the (otherwise well hidden) secret that it is Mila Kunis' Theodora who becomes the Wicked Witch of The West.
Why It Was Unbelievable: What do they take us for, mugs?
The Shawshank Redemption (1994)
The Spoiler: If the original title of Stephen King's novella, Rita Hayworth And Shawshank Redemption , gave a cryptic hint towards the film's ending, spare a thought for the people of Finland, who showed up to see Rita Hayworth - Avain Pakoom , aka Rita Hayworth: Key To Escape .
Why It Was Unbelievable: However you phrase it, it's a bit harsh on Marilyn Monroe and Raquel Welch.
The Spoiler: Sean Bean's supposed corpse was still warm from the pre-credits sequence when the titles gave him second billing behind Pierce Brosnan. Generous for a cameo… or proof he's not really dead?
Why It Was Unbelievable: If they'd waited another fifteen years or so to cast Bean, everybody would have believed in his death because, let's face it, that what Bean does best.
The Empire Strikes Back (1980)
The Spoiler: In an interview with fanzine Little Shoppe Of Horrors published in April 1978, Dave Prowse revealed that - shock, horror - Darth Vader is Luke's father.
Why It Was Unbelievable: It's a good job the Internet wasn't around in the late 1970s, although Prowse would probably have been out of a job. That said, it's not exactly the hardest twist to work out, given that the linguistic roots of Darth Vader can be traced to the giveaway title of 'Dark Father.'
Toy Story 3 (2010)
The Spoiler: There's always a danger of tie-in toys highlight plot details but in 2010, Fisher Price unveiled a playset relating to the Tri-County Landfill, home to the film's big third-act set-piece.
Why It Was Unbelievable: The prominence of the alien characters, allied to a big moveable claw, rather signposted how the day would be saved, even before audiences saw the heart-stopping scenes in the furnace.
Free Willy (1993)
The Spoiler: The ultimate in spoilerific marketing campaigns. Everything from the title to the trailer to the poster left little doubt how this one was going to end.
Why It Was Unbelievable: The fact that audiences didn't care, making Free Willy the 13th highest grossing film at the American box-office in 1993.
The Amazing Spider-man (2012)
The Spoiler: Sony drew flak from fans for its saturation marketing campaign. While no individual trailer was guilty of major spoilering, taken in tandem the surfeit of previews meant that audiences that seen a substantial part of the film long before its release.
Why It Was Unbelievable: So much footage was available that canny Vimeo user SleepySkunk created a 25-minute mini-version of the full film.
The Dark Knight Rises (2012)
The Spoiler: 13-year-old newcomer Joey King gave an interview six months before the film's release in which she confirmed, "I play young Talia al Ghul. I can't give too much away because I promised Mr. Nolan I wouldn't say anything. There are too many secrets about the character and the movie."
Why It Was Unbelievable: In her naivety, King hadn't realised that even mentioning Talia's name was enough to alert fanboys to the idea that the character might appear as an adult.
The Hateful Eight (TBC)
The Spoiler: Online leaks of screenplays are nothing new, but usually there's a film to go with them. In this case, details of Tarantino's plan to follow Django Unchained with another Western emerged after a select bunch of actors had been sent the script for a read-through.
Why It Was Unbelievable: Tarantino now considers the project well and truly spoilt, and at time of writing isn't pursuing it as a film project.
Planet Of The Apes (1968)
The Spoiler: A generation of kids has grown up knowing exactly how the sci-fi classic ends, thanks to Troy McClure's immortal musical, "Stop The Planet Of The Apes! I Want To Get Off."
Why It Was Unbelievable: More spoilers should come in rhyme. All together now: "Oh, my God, I was wrong / It was Earth all along."
Cast Away (2000)
The Spoiler: It's easier here to say what wasn't spoiled by the film's notorious trailer. Namely, nothing. The entire film - down to the last-act reveal that Tom Hanks escapes the island - is condensed into a bite-sized two-minute version.
Why It Was Unbelievable: Director Robert Zemeckis did it on purpose to improve the film's box office because - and we quote - “We know from studying the marketing of movies, people really want to know exactly every thing that they are going to see before they go see the movie. It’s just one of those things."
The Matrix Reloaded (2003)
The Spoiler: The Wachowski brothers were so intent on turning their hit movie into a multi-media franchise that, concurrent to the release of its sequel, they released a series of short animes (aka The Animatrix ) and computer game Enter The Matrix , both of which offer mild spoilers for events that take place during the movie.
Why It Was Unbelievable: Arguably, these don't count as spoilers because they are designed for the fans but - say - if you play the game first, there's little dramatic tension seeing Morpheus fall from a truck in the film because you'll have already played out the moment where Niobe rescues him.
Lone Survivor (2014)
The Spoiler: The film revolves around the travails of a four-man SEAL unit, but not only does the title helpfully reveal that only one of them makes it out, but the poster image shows us which it is.
Why It Was Unbelievable: The three other actors may as well have worn skull and crossbones motifs on their costumes, or dressed as Starfleet redshirts.
Dark City (1998)
The Spoiler: It was supposed to be a big twist that the world of Alex Proyas' sci-fi noir was controlled by the alien Strangers… until the studio panicked and demanded that a tell-all voiceover be added to the film's opening sequence.
Why It Was Unbelievable: You only have to look at the success of the similarly-themed The Matrix the next year to realise the stupidity of ruining the big surprise.
Thor: The Dark World (2013)
The Spoiler: Actor Clive Russell, who plays Tyr in the Marvel franchise, inadvertently revealed details of the film's post-credits stinger when he admitted, "I worked with Benicio del Toro on a scene in which he was meant to be quite angry.”
Why It Was Unbelievable: It's doubtful Russell is familiar with the intricacies of comic book movie etiquette. Clearly, all Marvel superheroes need a primer in what they're allowed to say.
Terminator: Salvation (2009)
The Spoiler: With the Terminator fanbase's attention focussed on Christian Bale stepping up to the big role of John Connor in his first post- Dark Knight blockbuster, was it really necessary to use the trailer to a) put the emphasis on Sam Worthington's mystery man and b) reveal that he's not really a man at all but a Terminator.
Why It Was Unbelievable: Looking back, 2009's "year of Sam Worthington" seems like a strange aberration in the history of cinema.
Children Of Men (2006)
The Spoiler: With a trailer that couldn't hide the story's belly-full of surprise, the entire first act became a protracted exercise in world-building.
Why It Was Unbelievable: Given the way Alfonso Cuaron shoots action, there's no need to emphasise plot at all here.
Snakes On A Plane (2006)
The Spoiler: Producers eagerly promoted the signature line of Samuel L. Jackson's B-movie horror, "I have had it with these motherfucking snakes on this motherfucking plane!" Chiefly because the line had been devised by online fans whipped up into a frenzy when the film became an unlikely Internet phenomenon during its pre-production.
Why It Was Unbelievable: This was a deliberate spoiler that backfired; the joke was better in the imagination than in fact, so nobody needed to bother watching the film just to hear Jackson say the line.
The Negotiator (1998)
The Spoiler: In 1998, pitching Samuel L. Jackson against Kevin Spacey was like Hollywood's equivalent of Ali vs Forman. It didn't need a trailer that clumsily revealed that the antagonists end up working together to defeat a common foe.
Why It Was Unbelievable: The trailer's give-away line ("Now you're gonna have to deal with both of us") never made the final cut. When even your director is embarrassed to use it, it probably should've stayed out of the trailer.
Iron Man 3 (2013)
The Spoiler: The perils of toy tie-ins were clear when LEGO unveiled its range of sets for the Marvel threequel. Not only did the appearance of one key character hint towards the identity of the film's big bag, but the 'Malibu Mansion Attack' set showed another major character donning the Iron Man suit.
Why It Was Unbelievable: Much of the freshness of the recently released The LEGO Movie was due to how well the film's twist was kept secret, but other movies' spoilers are fair game, it seems.
There Will Be Blood (2007)
The Spoiler: The film's best scene became fodder for American comedians within weeks of the film's release, with people queuing up to have a go at Daniel Plainview's catchphrase, "I drink your milkshake!"
Why It Was Unbelievable: While the dialogue was stripped of its context in the various parodies, it was still enough for alert newcomers to the film to guess the pivotal twist.
Funny People (2009)
The Spoiler: Billed as a return to 'proper acting' by Sandler, as the comedian who rethinks his life when he's diagnosed with cancer, the film's trailer was determined to lighten the mood by revealing the mid-film twist that he beats the disease.
Why It Was Unbelievable: Clearly, nobody wanted to risk upsetting the Adam Sandler fanbase by implying the star might not make it to the end credits.
The Usual Suspects (1995)
The Spoiler: Distributor Grammercy Pictures based its poster campaign on the notion that the film's biggest mystery was "Who is Keyser Soze?" which pointed cinemagoers in the direction of a twist they wouldn't otherwise have known was coming.
Why It Was Unbelievable: Bryan Singer and Christopher McQuarrie had based the entire project on the idea of having a line-up on the poster. It's a brilliant piece of marketing, and didn't need the Soze connection.
Terminator 2: Judgement Day (1991)
The Spoiler: Rewatch James Cameron's blockbuster sequel, and it's far from obvious during the film's first act that Arnie's T-800 is now the good guy. However, everybody knew that was the case going into the cinema, because the entire marketing campaign was predicated on Arnie telling everybody.
Why It Was Unbelievable: Imagine the shock of realising that the first film's roles had been reversed. Alas, it wasn't to be… although it must be said that there is plenty more to enjoy in T2 .
The Island (2005)
The Spoiler: The eerie first half-hour of Michael Bay's sci-fi thriller becomes rather redundant if you've seen the trailer, where pride of place goes to Steve Buscemi's spoilerific announcement that Ewan McGregor's character is a clone.
Why It Was Unbelievable: There's a Michael Bay film with a structured plot?
Double Jeopardy (1999)
The Spoiler: It was probably inevitable from the moment they titled the film, but it's still self-defeating to spell out the film's plot in the trailer by having a character explain the concept of double jeopardy: "That means when you leave here, you can kill him and there's nothing anybody can do about it." OK, no need to see that film, then.
Why It Was Unbelievable: They might as well have taken a leaf from the classic American quiz show and only show scenes from the end of the film, and let the audience guess what happened earlier.
The Spoiler: OK, we're cheating on this one, because it's a film that spoiled a TV show. Namely, Judd Apatow's This Is 40 , which should have come with a spoiler warning for anybody who hadn't reached the end of J.J. Abrams' classic. Hollywood, you should know better.
Why It Was Unbelievable: Apatow knew exactly what he was doing; the spoilers are an ironic commentary on the film's subplot about daughter Sadie's efforts to get to the end of the series to find out what happens.
Barton Fink (1991)
The Spoiler: What's the deal with John Goodman's character? Well, if you were unfortunate enough to watch this for the first time on DVD, the menu montage helpfully makes it clear that he's a complete psycho.
Why It Was Unbelievable: Clearly, the sensible thing to have done would be to show a single shot of peeling wallpaper in Barton's hotel room.
Charlie's Angels: Full Throttle (2003)
The Spoiler: Just about the only redeeming feature of McG's sequel is watching Demi Moore camp it up as a 'dark angel,' but much of the surprise was robbed by a publicity campaign that concentrated on the actress' comeback as the film's villain.
Why It Was Unbelievable: With its fights and costume changes and giggling trio of stars, Full Throttle had more than enough material to promote the film without mentioning Moore at all.
The Amazing Spider-man 2 (2014)
The Spoiler: The film isn't even out yet, but most fanboys have pieced together how Felicity Jones will be involved from some unguarded comments she made last year: "It's all quite shrouded in secrecy, but I'm the Goblin's girlfriend - I'm in a relationship with him, and his accomplice. I'm on the dark side."
Why It Was Unbelievable: Shrouded in secrecy? Not any more, it isn't.
Dream House (2011)
The Spoiler: Did the Daniel Craig thriller flop because of its ludicrous twists? Or was it because those ludicrous twists were telegraphed by its tell-all trailer? Or, heck, even by the film's very title?
Why It Was Unbelievable: Watch this, and realise it's only a matter of time before somebody tries to make Donald Kaufman's serial killer screenplay, The Three .
Million Dollar Baby (2004)
The Spoiler: While critics wrestled with the dilemma of how much of the film's plot to give away, given its unexpected, tragic third act, disability activists - angered by the film's perceived advocacy of euthanasia in killing off the quadriplegic Maggie Fitzgerald's - had no such dilemma.
Why It Was Unbelievable: Even as reviewers spent their word count saying, "I can't tell you what happens," the news sections of the same outlets were busily debating the film's twist.
Captain America: The Winter Soldier (2014)
The Spoiler: Oh, Marvel, when will you ever learn to stop actors from talking to the press? This time, it's Robert Redford, who waxed lyrical last year about taking on the role of S.H.I.E.L.D. boss Alexander Pierce. Why did he take the role? "I like the idea of playing a villain. I did that just because it’s a different thing for me to do.”
Why It Was Unbelievable: Iron Man 3 proved that Marvel could keep the lid on a twist… but increasingly, it looks like that was only because Ben Kingsley had the gumption to keep his mouth shut.