Foreshadowing is a fun way for creators to hint at where their stories will go. Even if those hints go over the audience's head, planting the seed in our subconscious makes the eventual reveal all the more satisfying because it fulfills an established expectation. It's a device that's used a lot in superhero media where protagonists are usually forced to deal with the consequences of the life they've chosen to lead, whether it's a supervillain of their own inadvertent creation or their good intentions only making a situation worse. Post-credit scenes, or "The Stinger," at the very end of a movie, openly tease what's to come in the next installment of a series, like Batman being passed a Joker playing card in Batman Begins, or Thanos' "I'll do it myself," line in Avengers: Age of Ultron.
More often than not, we have to already know the ending of a film or TV show to catch these clues. The Matrix spends most of its first half smacking you over the head with biblical references, but you wouldn't get the significance of them unless you re-watched the film. Knowing that Neo is destined to become humanity's prophecized champion makes lines that are said very early into the movie like, "Hallelujah. You’re my savior, man. My own personal Jesus Christ," suddenly feel very on the nose. For adaptations, prior knowledge of the source material makes for an enriching experience the first time around, as is the case for Marvel and DC comics fans.
As we'll be discussing plot twists, endings and character fates in this list, watch out for major spoilers ahead!
15 AGE OF ULTRON: PEACE IN OUR TIME
Two early clues are dropped to tell us that Ultron's arrival will be Tony Stark's doing in the second Avengers film. One is visual. When Tony's Iron Legion are deployed to keep the peace, one of the drones takes a molotov cocktail to the head making it resemble Ultron's face. This same drone later becomes the robot's first body.
The other clue is verbal. When Tony talks about Ultron heralding "peace in our time," he's quoting British Prime Minister Neville Chamberlain who tried to prevent WWII by signing a deal with Germany in 1938. Just like Chamberlain, Tony's plan disastrously backfires on him.
14 SMALLVILLE: A COLORFUL CAST
Before the Arrowverse and Gotham, DC comics were represented in live-action on the small screen by Smallville, which chronicled the adventures of a young Clark Kent before his Man of Steel days. This premise wasn't a secret, but the show still found ways to subtly weave the future legacies of certain characters into their past.
Clark was rarely seen not sporting red, yellow or blue -- the colors of his Superman suit, of course. Even the Kent's farm uses the same palette. Lois Lane usually wore a similar color combination, the same as her various iterations, while Lex Luthor and Tess Mercer stuck to purple and black, the signature colors of the Luthor family.
13 THE AVENGERS: EYES ON THE PRIZE
In the first Avengers movie, Loki allows himself to be captured by S.H.I.E.L.D. While imprisoned in the helicarrier, a sly Black Widow manages to tease the truth out of him: his plan lies with Bruce Banner, or more specifically -- the Hulk. But he actually gave the game away before then.
If Black Widow had kept a closer eye on the Asgardian prince when he first arrived she might've spotted him direct a grin in Banner's direction. That's right, the trickster god was so overconfident, he couldn't help size up his prey the moment he saw him. Another example comes when Steve tells Tony he isn't someone who'd sacrifice himself for others, which Tony (almost) proves wrong towards the end.
12 YOUNG JUSTICE: COUSINS, ONCE REMOVED
Throwaway lines can become painfully foreboding in hindsight. The animated series Young Justice, which follows DC Comics' younger heroes and heroines as they bust out from their sidekick roles, ended its second season on a tragic note in the episode, "Endgame." As the Earth's magnetic field starts to destabilize, it's up to the Flash, Kid Flash and Impulse to fix it.
How do they do it? Well, guess. Using their combined speed, they generate enough kinetic energy to stabilize the field, but at a great cost: Kid Flash's life. Too much energy absorption causes Wally West to be erased from existence. This explains why the time-displaced Impulse refers to him as "my first cousin, once removed," in "Bloodlines." He means it literally.
11 BATMAN BEGINS: BRICK BY BRICK
Christopher Nolan's Batman origin movie often gets overlooked next to its flashier sequels. Like most "firsts" in a series, it foreshadows much of what's to come in Bruce Wayne's life, most of which we're already primed to expect because at this point, who doesn't know how Batman "begins?"
What we don't know is how Nolan's take will end, though a line from Bruce to Alfred not long into the film forewarns us. "This place is a mausoleum. When I have my way I'll pull the damn thing down, brick by brick." He's talking about Wayne Manor, and unwittingly gets his wish later when the League of Shadows burn it down.
10 ULTIMATE SPIDER-MAN: EVIL IN A BOTTLE
An episode of Disney's Ultimate Spider-Man cartoon dropped a great sneaky reference to several of the wall crawler's most infamous foes. In "The Lizard," several test tubes can be seen in Doctor Octopus' lab holding animal DNA. Seems pretty innocuous, right?
That is until you realize that the animals are a lizard, rhino, scorpion and vulture. At that point, Rhino and Lizard had already shown up in the show and the groundwork for Scorpion's arrival was laid, so it stood to reason the writers were telling us to look out for Vulture next, and maybe even that Doc Ock was behind some of his fellow supervillains' monstrous transformations.
9 THE AMAZING SPIDER-MAN: PETER'S FUTURE
An origin story as well-known as Spider-Man's means few people will be left shocked that dorky teenager, Peter Parker, becomes the web-slinging hero in a Spider-Man film. But that doesn't stop filmmakers from signposting this fact anyway. Early on, The Amazing Spider-Man shows Parker swinging around, Tarzan-style in a warehouse -- something he'll do with webbing later.
An even smaller detail can be seen when he's trying to nail the equation needed to help a rat re-grow its leg. Upon finally succeeding, you can just about make out the warning, "Severe mutation detected," on the screen, an affliction that will soon turn Peter from man to, well, you know.
8 POWER RANGERS: MACK'S SECRET
Power Rangers: Operation Overdrive introduced us to a very different kind of Red Ranger -- one that wasn't as human as he looked. Mack Hartford's billionaire father was so desperate for a son he artificially built Mack himself. Though neither we nor Mack discover this until much later, the signs were there the whole time.
The family butler once reminds Mack not to see himself as one of dad's "possessions," and there are many instances when Mack is unable to do things than the rest of the human team can. The cherry on top is a Halloween special in which his costume of choice happens to be a robot. (Because when is Power Rangers ever subtle?)
7 IRON MAN: IRON MONGER
Iron Man's plot twist -- that Tony Stark's long-time mentor, Obadiah Stane, was the real Big Bad -- would have come as a surprise to most of the audience. Marvel Comics fans, however, might have seen it coming thanks to a pretty obvious namedrop the malicious businessman makes after Tony's homecoming.
Tony tells his business partner about his ethical wake-up call, decisively stating that Stark Industries would switch from fuelling war to developing clean energy. "We're ironmongers, Tony," Obadiah tries to reason with him, "we make weapons." Iron Monger is an Iron Man comics villain, so the line strongly hints at the villainous mantle he's secretly taken up.
6 VOLTRON: KEITH'S ALIEN DNA
Towards the end of the second season of Netflix's Voltron: Legendary Defender -- a reboot of the '80s animated classic -- it's revealed that one of the Paladins, Keith, is half Galra -- sworn enemies of Team Voltron. Other than his Galra-esque features, the show dropped clues to this from the start.
In the very first episode, Keith has to recover the Red Lion from a Galra vessel, and when facing Zarkon in the Season One finale, the tyrant notices Keith's Galra fighting style. Keith is also the only one able to use Galra devices without artificial aids, and he has a Galra symbol on his knife. It was right in front of us the whole time!
5 CIVIL WAR: FATEFUL SEATING
Though this one covers two different movies, it's far too interesting for us not to include here. During the scene in Captain America: Civil War in which General Ross gives the Avengers an ultimatum on the Sokovian Accords, the seating arrangement around the table seems to be a big Infinity War spoiler.
Those sat on the left -- War Machine, Black Widow and Captain America -- survived the Thanos snap, while those on the right -- Scarlet Witch, Vision and Falcon -- weren't so lucky. Meanwhile, Tony Stark is positioned away from the table behind them, mirroring his position off-Earth during said snap. Clearly that table is cursed.
4 AVENGERS: FRIEND OR SKRULL?
Skrulls are only just making their appearance in the MCU but over on the small screen, they had a significant role in Avengers: Earth's Mightiest Heroes. The first blink-and-you'll-miss-it detail happened in "The Masters of Evil" episode, showing a newspaper story about a man alleging he'd been replaced by an alien.
The man was a Baxter Building resident, pointing us in the direction of the Fantastic Four. In "The Private War of Doctor Doom," these suspicions come to the surface when Tony Stark accuses Reed Richards of neglecting his wife. Reed mentions Sue's been closed-off, and suspects she's hiding something. Hmm, now what could that be..?
3 THE INCREDIBLES: NO-ONE IS SPECIAL
In the first Incredibles movie, jealous supervillain Syndrome turns out to be Mister Incredible's former teen sidekick -- a sidekick he never asked for. Spurned by his superpowered idol, he became embittered about his own lack of powers, which becomes the motivation behind his switch to villainy.
In his supervillain monologue, Syndrome tells us that he dreams of a world where everyone is special so that "no-one will be." Eerily, we heard this very same sentiment from Mister Incredible's eldest son towards the start of the film. When his mom reminds him that "everyone is special," Dash mumbles that's just another way of saying "no-one is." Clearly Dash and Syndrome aren't too different.
2 JUSTICE LEAGUE: HAWKGIRL'S TREACHERY
The reveal of Hawkgirl's identity as a double agent for her invasion-plotting home planet would have come as a shock for most viewers of Justice League: The Animated Series, but the truth was peppered throughout the show for us to spot. In retrospect, there were times when she almost blew her cover.
She was particularly wary of Martian Manhunter's mental probing, blocking him from her mind and quickly shooting down his one-time offer to learn more about Thanagar from Brainiac's database. She also angrily demands Doctor Fate disclose what he finds out from Thanagarian runes, which we mistake for homesickness.
1 THE DARK KNIGHT: A JOKER INSIDE AND OUT
The highly-acclaimed second chapter of Christopher Nolan's Batman film trilogy starts with a bang: a bank robbery. As is the case with many heists, the perpetrators are masked to hide their identities, and given we're in Gotham City, the choice of a clown mask can only mean one thing.
Eventually, our suspicions are confirmed. The Clown Prince of Crime is the ringleader. But, fans of the '60s Batman TV series may have worked this out straight away. The Joker's mask is actually a replica of one that Cesar Romero, the first live-action Joker, wore in the episode, "The Joker Is Wild," a crafty nod to Batman history.