In the fan novelization of Ace Combat 7: Skies Unknown called Three Strikes, in the chapter Long Day, after the mission is complete one of the retreating drones breaks off and goes after the withdrawing Count, Tabloid and Trigger. This is the first sign in this story of the drones acting out on their own. Far later, like in canon, in Last Hope, it comes up again when a group of them starts to attack Strider Squardron having gone autonomous due to lacking a drive.
Death in the Golden Hour, the prologue to Sixes and Sevens, Emily Gower notes her hunger after smelling human blood in the distance, indicating that by this time she has gained the vampiric attributes of her comics counterpart.
Tom gets along with the Hork-Bajir more than the other humans in Kref Magh. It's implied that he semi-deliberately becomes a Hork-Bajir nothlit for this reason.
At the end of Welcome Home, Tom asks Tobias if there's a weapon so dangerous that no-one could be trusted to use it. This sets up the quantumn virus plan in Destroyer of Worlds.
There's a brief mention of a blonde woman visiting two children on life support in THX 1138. She matches the description of Margaret from Ghost in the Shell, who gave birth to several children as part of the Yeerks' experiment to create Empty Shells.
In Ghost in the Shell proper, Tom and Bonnie discuss how morphing works, and it's mentioned that it doesn't heal all injuries — Alloran still has a few battle scars despite morphing countless times — and Tom muses that he's the perfect host now that he has the morphing power. A few chapters later, Tom freaks out about the idea of the Yeerks returning, and tries to permanently cut off two of his fingers so he won't be considered a viable host.
Later, Margaret is described as wearing a skintight top. It turns out that she's morph-capable, so that's presumably her morphing suit.
Bleach (S) Abridged exaggerates the canon foreshadowing that Ichigo's inner hollow is the real Zangetsu, while the Old Man is his personified Quincy powers greatly for comedic effect; it'd be an Open Secret if Ichigo wasn't so dense. The Hollow repeatedly calling himself Zangetsu happens in in canon, but unlike in canon, Ichigo assumed that the Old Man was his zanpakuto spirit in their first meeting and got a Sure, Let's Go with That response, and during Ichigo's battle with Hiyori, the Hollow reacts to Hiyori cracking Zangetsu's blade by yelling about how " that bitch just chipped me!", and Shinji comments that he's unusually articulate for a Hollow (though, to be fair, he's more talkative than his canon self as well). And on a completely unrelated note, shinigami who drop into Ichigo's bedroom unannounced tend to compliment his Quincy sheets.
Happens in every other scene in Hammered Down. When you get to the climax, it's like everything just decided to go boom.
Koyonagi, the Zanjutsu department head of Shin'hou Academy and Ichigo's friend in Swinging Pendulum, is noted to have a lot of knowledge of Kidou despite it not being his specialty and manages to teach Ichigo the proper mindset for casting. Asuka and Rangiku note it strange that Koyonagi acts as Ichigo's guidance counselor when he's usually mean and dismissive to both students and faculty. Koyonagi is a former Kidou Corps Commander working for Central 46, hoping to recruit Ichigo.
In Nightfall, Chilli acts unusually tired, and she also coughs the morning after the hot sauce was bit. This foreshadows that the vampires don't exist and it was All Just a Prank cooked up by Chilli, who was the one biting the food in the night.
Xendra foreshadows Willow's coming addiction to magic back in season 4 when she suggests using Xander's magical transformation to heal some minor bruises and scrapes, seemingly just for the sake of using magic.
Calvin: I wish Dad would put me on my OWN boat. Mom: Don't be silly, Calvin. If you were on a separate boat, you'd get lost out at sea!
Then there's the beginning of Chapter 6:
Mom: Dear, Calvin has more of a chance of meeting a sea monster then hitting the Bermuda Triangle.
In the Season 3 finale of Calvin & Hobbes: The Series, the MTM starts taking a while to do anything, earning the ire of the gang. There's also Hobbes' cowardice, which is rather prominent in this episode. When the latter mocks the deceased former as useless, Calvin is infuriated and belts out a "The Reason You Suck" Speech.
At one point, the MTM complains about his low battery which prevents him from teleporting everyone from the station.
The drifting canoe from "Camping Trip Part 1" is described as being a quarter-mile away from the island. In Part 2, Calvin combines this with twoChekhov's Guns and a Chekhov's Skill in order to get the canoe back to shore.
The side story "Prelude to a Season" is entirely made of this. Certain cryptic hints throughout Season 5 follow suit, building up to the season finale and beyond.
A Cryptic Conversation in "Dark Laughter Part 1" foreshadows the strange events facing the group in the rest of the episode and Part 2, in addition to the above.
During the Prologue, Monokuma blames the students' memory issues on the Monokubs botching the restoration procedure. The Kubs don't show up in person until Chapter 2, well after the first trial.
While reviewing all the prizes offered at the casino, the investigators note how odd it is that two seemingly unrelated items have been positioned next to each other. During the first trial, it's revealed that there was a very good reason for this: both were weapons, with the more innocent-looking item having a hidden blade.
As the first trial begins, Leon asks whether the victim might have left a Dying Clue behind, and Chiaki mentions looking for a concealed weapon. Both Call Backs prove relevant, combining with another Recurring Element: once again, the culprit was actually attacked by their victim, though the situation is more complicated than simply a matter of self-defense.
In the beginning of the Power Girl fanfic A Force of Four, Badra takes three Kryptonian outlaws to planet Mars. It might look like a random choice, but it is not: several chapters later it's revealed that Mars — is her backer.
In the Supergirl story Hellsister Trilogy, Black Adam is the first enemy fought by Dev-Em. Many chapters later, Dev would meet Shazam and Captain Marvel himself.
This happens all the time in the Supergirl (2015) fic Future Shock, but probably the most notable example is M'Gann noting that people can get shot in the head for making certain statements.
While singing his Villain Song in the tavern, K. Rool throws a dagger that hits a Kremling dummy, with more dummies of his Krew next to it. The dummies would have no reason to be in the tavern, but they are in the basement where K. Rool was previously established to be hiding out, hinting at the reveal that the entire musical number was in his head.
The other characters mention K. Rool has been missing for 10 years, setting up The Stinger where he receives his invitation to Super Smash Bros. Ultimate in the mail.
Done repeatedly, with varying degrees of subtlety, in the Inquisition AU Beyond Heroes: Of Sunshine and Red Lyrium. In this story, Bethany Hawke is the Inquisitor, with Varric as the Non P.O.V. Protagonist, and much of what Varric says or thinks turns out to be foreshadowing for later events. To give one non-spoiler example, before the march to Adamant, Varric jokes that “I happen to be an extremely valuable commodity in the Inquisition, Hawke. I have to be protected.” Later, in the Arbor Wilds, the words of a Red Templar make it clear that the Elder One has ordered his forces to specifically target Varric, because his death would devastate Bethany so deeply that it would likely be her undoing.
In the Dragon Age: Inquisition fanfic Walking in Circles, Evelyn revealed to Solas after his meeting with Monette that the First Enchanter is more than she seems underneath all those flowers and teas in her room, not to mention the flower the woman gave Solas is actually poisonous. Much later, Monette gives Evelyn some special tea that helps the latter remain awake despite being drugged for the kill by the Templars.
At one point, one of Evelyn's friends, Keldra, has to take her clothes to the laundry chamber due to her period staining them. When she asks Signy if the latter would like Keldra to deliver her own things too, Signy declines. Later, it turns out that Signy is a blood mage using her period blood as materials for practice, instead of risking to cut herself like others.
At exactly two points in Ed, Edd n' Eddy Z, characters' lines that include foreshadowing have flashing "EPIC FORESHADOWING" text underneath the text box.
In The Fifth Act a Nibelheim local comments that Mayor Lockhart doesn't like Cloud because he's afraid "he'll leave a trail of bastards" Guess what Cloud's father did?
Ms Strife freaks out at the sight of Cloud and tries to shoot him because his "brother"note Cloud's father and his family did something horrible to her and she doesn't want them to take her son. There is a good reason to why she freaked out.
At one point Cloud muses on how to destroy Jenova, remembering that she's vulnerable to mundane means and that a few good Fires should finish her off. Genesis does exactly that, firing off a bunch of Firagas and burning Jenova to ash.
When Vincent first tries to talk down Cloud from killing Sephiroth, Cloud utterly refuses to acknowledge such notions and wouldn't even lie or budge even if it meant losing Vincent as an ally.
Springtrap and Deliah: During their movie night, Deliah says she could never hate Springtrap, unless he was a dead serial killer of course, but that could never be true. True to her word, she becomes afraid of him in both endings when he admits the truth.
In build your wings on the way down, note how Alexander gets very little mention by Edward, despite being Nina's pet? Later, Edward notes that he needs something to sacrifice to the Gate if he wants to restore Nina without losing more limbs. Alexander is sacrificed to the Gate by Ed to restore Nina.
Under the Weather foreshadows Janine catching Egon's cold by her sniffling, mentioning having an itchy throat, and getting chills. Venkman even wonders if she's getting sick, but this just irks her. Also, Peter teases Egon about liking Janine, which foreshadows them becoming a couple in Love Sick.
Kyon mentions his uncle is called Keiichi in one early chapter of Kyon: Big Damn Hero. Later on, he ends up in Hinamizawa for Golden Week, staying with said uncle. Taking it even further, the Fictional Document at the beginning of the first chapter indirectly references Hinamizawa Syndrome.
A Thing of Vikings foreshadows with a vengeance. Some plot developments foreshadowed in the first ten chapters don't pay off until dozens of chapters later, and offhanded mentions in one chapter can come back later as major developments.
In chapter 2, Hiccup has a daydreaming moment of various inventions during a public reading of a saga in his honor. 23 chapters later, one of his inventions from that daydream is used as air-dropped firebombs on an invading fleet.
Also in chapter 2, Ruffnut notices Mildew bothering the visiting merchant, Johann. Mildew wants to know where his order of Oleander concentrate—a highly toxic poison he uses to slay dragons—is, and Johann is telling him that it isn't available this year. By Johann's next visit in chapter 28, Mildew has pulled a vanishing act, and Johann mentions to someone else in chapter 49 that he had to sell the Oleander to someone else at a loss—and that unknown party uses it to try to poison people at Berk's next spring festival... in chapter 58.
Asylum of Doom: All Gaz sees of the thing that startles her and makes her fall down the stairs are a pair of red eyes in a white face. Upon meeting the albino Maddie in the past, she gets a feeling of familiarity, and at the end of the story, it's shown that what startled her was an albino bat that is then implied to be Maddie's ghost in another form.
Early on in Gaz and the Exchange Student from Hell, the Membranes' foreign exchange student guest, Circe, presents as an art project a model of a baby cuckoo taking over a robin nest. At the story's climax, it turns out that Circe herself is cuckoo-like demon, who is seeking to replace Gaz in the Membrane family.
Invader Zim: A Bad Thing Never Ends: Near the end of Chapter 2, Dib and Gaz discuss how the CEO of Coathanger Electronics is moving to the City to set up his new corporate HQ. The end of the next chapter reveals that this is more than a random bit of background information, as we learn that the company is conducting shady genetic experiments, suggesting they're going to be very important to the plot going forward. This is confirmed in Chapter 7, when said CEO is revealed to be part of the Big Bad Ensemble.
My Hostage, Not Yours: About midway through The Inevitable Takeover, Gaz has a nightmare that she loses control of her pyrokinesis. During the climax, her rage at the Swollen Eyeballs causes this to come to pass, before Zim is able to talk her down.
The plot of Episode 5 (Dib desperately trying to get ahold of a book on vampire hunting) is set up by a throwaway line of dialogue in Episode 4.
Early in Episode 18, Gaz proves her gaming skills with the motto "play smarter, not harder". She ultimately beats Iggins in their tournament by focusing on winning on points, rather than trying to rush through each game, the way he does.
Season 2: In Episode 12, GIR is watching the Scary Monkey Show at the beginning of the chapter, before the Trapped in TV Land plot kicks off. The climax sees the group meeting the actual Scary Monkey.
When Red interrogates the surviving kryvtor assassin in The Smeet, the prisoner mocks him, telling him that he wouldn't be able to protect Ilk forever and one day he'd make a mistake, lamenting that he wouldn't be there to see it. This later proves to be true in Lost when Red has a monstrous argument with Ilk and slaps her, pushing Ilk to run off and nearly get killed when a stick goes right through her.
Throughout Lost, Blue mentions that his father and grandfather left for a suicide mission and never returned. Additionally, Red finds an uncanny resemblance between Blue and the kryvtor assassins that nearly killed him. Later on, it is confirmed that Blue's family members and the kryvtor assassins are one and the same.
Jonathan Joestar, The First JoJo: Near the end of chapter 15, Jonathan mentions how he had hoped the anomalies had brought Danny and George back to life, which ends up happening in chapter 19.
In Patient, there's quite a bit of foreshadowing to the twist that Dorothy is in Oz, not Kansas, such as Eureka being pink and her sigh sounding human.
Why are you here now? I want to ask her. But you're ignoring me again. Maybe that's for the best. Otherwise, you might notice me capitalizing the Body. When you do notice, I'm gonna need you to get really cool about a lot of stuff really quickly. Like. Hoo boy.
Harrow can produce saltwater on command. That's not actually a necromantic ability.
(Note to self - should probably look into the whole saltwater body fluids on demand thing. I'm not sure why it keeps happening. Definitely not part of the whole perfect Lyctor thing I anticipated.)
Mercymorn calls Harrow a "cuckoo." Cuckoo birds steal into the nests of other birds and pretend to be something they're not. Yeah, she wasn't calling her crazy.
Ianthe is repeatedly getting worn down by her incomplete Lyctor transformation. It turns out that, with Harrow being a success this time around, the Saint of Duty has been trying to kill her. Both Gideon and Harrow are horrified that they never realized it.
The Ace Savvy Extended Universe: In one story, the heroes comment on the unfortunate reality that sometimes the police go bad. Later on in the story, the villains do convince the police to side with them.
April Two Rules, the majority of the Loud siblings talk about having a plan to get revenge on Luan for her April Fools behaviour, and they sing a song admitting they plan to "lie a little". This foreshadows the fact that most of the events of the story following that song were All Just a Prank.
Burning Secret: Several things foreshadow that someone set up the fire to happen:
When Lincoln sees the beaker on the floor of the lab, he can’t see how it could have fallen.
Lincoln notes that it’s odd that one of the two paper towel dispensers isn’t on the wall. Then, when he takes the paper towels out, there is a “light scraping sound”.
The police are certain that it was arson and reveal that the liquid Lincoln cleared up was a fire starter. He notes that this doesn’t make sense.
The Edgy House has several oddities that foreshadow the fact that the whole story was all one big joke.:
Lincoln mentions that Lynn Sr. came back from a trip with baby Luan and said to Rita, "No, she's not adopted", implying that Luan was the baby of a woman he cheated with, yet somehow convinced Rita that Luan was hers.
Lori is said to have given birth to the twins when she was eleven, which, while not impossible, would be very biologically implausible.
In Mystery of the Self-Loathing Loud, Lori starts writing dark poetry with Lucy. This turns out to be because she was the writer of the suicide note and was trying to cope.
Lynn Sr. and Rita leave everything in their will to their seventeen-year-old daughter Lori, which, as Lori notes, would be a foolish thing to do.
Lori mentions not being able to remember her parents' funeral, or any other such details. This would be very odd not to remember, but dreams often do have random Time Skips.
Lori is the only one who seems to be mourning her parents' deaths; her siblings are being oddly nonchalant. For instance, Luna and Luan are still making song references and jokes respectively, and they even tell Lori that, because she's in charge, she has no right to be sad.
One of Lori's siblings (it's unclear who) mentions that they've taken the temperature of the youngest one, Lily, and she appears to be running a fever. However, Lily never seems out of sorts for the rest of the story.
born of hell('s kitchen): Peter is noted to be extremely energetic and given to hug very tightly his parents, while accepting his mother's embraces in spite of her worrying she is using her Super-Strength and about to squish the boy. He's actually growing into his own Super-Strength with the necessary stamina and resilience, so didn't notice his mom's hugs were rather dangerous for the health.
There's also several elements pointing towards Peter's upcoming superhero path career — his clothing already contains blue and red, his clinginess gains him to be nicknamed "spider-monkey" and he claims Black Widow is one of his Top Five heroes because spiders are awesome.
Weightless: In one of the first chapters, Shepard went rampage on the Citadel after talking to Saren. Later, Liara mentioned that in Shepard's memories, there was a starved figure who looked a lot like Garrus. Sometimes, Shepard would think about a person who was the first one that showed her kindness. They seem irrelevant and random at first, but then the author reveals about Shepard's true connection with Nihlus.
Subverted with another clue: When Shepard talked with Sidonis, she mention that she once had a lover, who was dead now. After the reader knew about Nihlus, they would think that she was talking about him. She was actually referred to Garrus, since to her, he died (at least in the spiritual sense) once.
ProtoMan mentions in Episode 4 that if the ion bomb had been any bigger they'd all be dead. In episode 6 a much bigger ion bomb is seen, and it's in danger of exploding.
Blueprints for Splash Woman are seen in the interlude to episode 8. Wily also mentions a Project G-2.
Chapter 1 states that a robot cannot self-terminate at the behest of a human. This saves Drill Man in episode 8.
In episode 7, ProtoMan stops Wily in the middle of testing a pain program on a Metool. The whisper in Wily's head comments that he should use it on ProtoMan. In the episode 10 epilogue, he does.
In Episode 11 the Conduit mentions a third, female associate. She is seen later on, as is a fourth associate.
In the very first paragraph, Dr. Light is mentioned to attend the New York Philharmonic regularly. In the original cartoon, he is shown to love classical music in "Cold Steel".
The machine Rock shoves at Wily and Proto Man in "The Beginning" was a prototype of the dream wave machine used in "Mega Dreams".
At the World Robot Expo, Roll tries to get tickets to Fun World, the setting of "Bad Day At Peril Park".
Governor Parson was hoping to run for another term, but then he cedes the state to Dr. Wily, setting up Deacon’s landslide election victory in "Bro Bots".
When Proto Man and Roll are trapped underground, Proto Man mentions that he listens to Cold Steel.
Mega Man’s doubts that lead him to see Dr. Petto in "Mega Pinocchio" begin in "The Big Shake" when Dr. Light tells him to focus on finding Dr. Wily instead of Roll.
Ring Man and Magnet Man talk about Metal Man, who appears in the cartoon episode "Future Shock". Metal Man debuts not in "Future Shock", but in "20,000 Leaks Under The Sea".
When fighting Wave Man, Mega Man notices his harpoon gun and wishes he had one, in a nod to the second season's marine gear.
Leave for Mendeleiev: Adrien/Chat Noir's behavior when Lady Wifi mistakenly 'outs' Chloé as Ladybug foreshadows a lot about his future conduct:
He completely dismisses all warnings about the importance of keeping their secret identities secret, casually referring to Ladybug by what he thinks is her real name and offering to reveal himself in exchange. This total disregard not only shows how little he respects Ladybug's wishes or boundaries, but hints at how little he's going to care about Lila's request that Adrien not tell anyone that she's supposedly Volpina. So when Mime takes Lila hostage, he outs her without a second thought.
After the battle, when Ladybug ducks into a closet to detransform, he stands outside and insists that there's no point in hiding her identity anymore, completely ignoring her clear discomfort and showing that he doesn't respect her boundaries at all, illustrating how he's going to continue chasing after her secrets over her protests.
Adrien only accepts the notion that Lady Wifi was mistaken after seeing Chloé outside the hotel while knowing that Ladybug was still inside. Later, a similar situation arises when he sees the time-displaced Ladybug talking to Marinette and Ondine, convincing him that Marinette couldn't possibly be Ladybug like he suspected.
Adrien's complete attitude shift towards Chloé during this period also illustrates his way of thinking. He only cares about his Childhood Friend's crush on him when he mistakenly believes that she's Ladybug; along similar lines, the moment he's convinced that Marinette can't be Ladybug, he snubs them without a second thought.
The One to Make It Stay: In the story Master Fu tells Marinette about his past, strong parallels are drawn between his history and recent events... and not with the obvious target. While he's offering her advice about Alya, his Evil Former Friend Bo acts far more like Chat Noir. Bo and Fu used to be partners as well as friends, with Bo fooling around, refusing to take things seriously, and being underestimated due to his love of joking around. Yet Bo proved to be Secretly Selfish, turning on his partner in the name of personal gain... much like how Chat Noir blows off Ladybug and feels entitled to her love.
Throughout "Rogercop", several references are made to the upcoming mayoral election. The next episode, "Darkblade", covers the results of said election and the fallout thereof.
Keep Your Friends Close: The villain team emblem depicts rabbit ears (Izuku) sticking out of a steampunk top hat (Hatsume), surrounded by a lavender cat (Shinso), a red and black snake (Momo), a shadow of a bird (Tokoyami), a violet fox with headphone jacks coming out of its ears (Jiro), a grey and pastel hummingbird (Hagakure), and a rust-colored octopus (Shoji). All of the animals have their eyes closed, representing the fact that all of the villains except Izuku and Hatsume are Double Agents working for the heroes.
Anthropology: In the first chapter, Lyra tells her cutie mark story to the CMC. In the flashback, she was one of the last ponies in her class to get her cutie mark and learn magic, and one night she heard her parents discuss it:
Lyra's Mother: "You know that Heartstrings has been struggling in school." Lyra's Father: "Some unicorns just take longer to learn magic, that’s all. Things will come to her in time." Lyra's Mother: "But what if it doesn’t? It’s been too long now. No magic, no cutie mark. What if it’s all because she’s –" Lyra's Father: "Heartstrings is a unicorn. It’s that simple. It’ll all come in time."
In her dreams, Lyra is a human and is exploring a big city. She actually ends up in New York.
Throughout the story, Lyra is told that she should act like a normal unicorn by her parents and Bon Bon. All this leads up to the revelation that Lyra isn't a normal unicorn. She is actually a human.
In the Asylum (Daemon of Decay) universe, we are introduced to Rarity in chapter 12, who is Twilight's case worker in this world, who gets into an argument with Applejack about Nurse Ratchet; specifically, her views on Keratotomies, calling her a 'heartless butcher'. Later in the chapter, Twilight asks Rarity why she stopped being a fashion designer, and is told she 'had her reasons'. She then inquires after Sweetie Belle, offering to donate her old Smarty Pants doll to her. Rarity seems deeply offended and rushes off. In chapter 17, we learn that a Keratotomy is the Unicorn equivalent of a lobotomy- removing the horn, along with the part of the brain that channels magic. It is a common procedure, and could happen to Twilight if her treatment fails. Then, at the very end of the chapter, it is revealed that Sweetie Belle underwent such a procedure and is now a drooling vegetable.
In chapter 9 of the first story, Cheerilee mentions that one of her students has a tendency to be rude and may be a problem during their class, and that one of her parents is even worse. While the student in question turns out to be too scared of Swift-Pad (what with him being a wolf) to speak out in class, her mother shows up later and is instantly rude and nasty to him, being unaware of who he is.
During the events of Diplomat at Large, Discord mentions having encountered someone who'd make a good Lady of Lies... if they weren't a complete and utter sociopath. In chapter 10 of Diplomacy Through Schooling, after Cozy Glow is arrested, he brings up the subject again. When Twilight mentions it to her friends later, they put two and two together to figure out Cozy was the one he was referring to.
Loved and Lost, an extended retelling of "A Canterlot Wedding", has several examples.
Before Prince Jewelius is revealed to be the true Big Bad, there are several hints that he may not be as nice as he presents himself to be. When Rarity praises Princess Cadance's wedding, he glares angrily for a split second as foreshadowing to his status as a Green-Eyed Monster in regards to his elder cousin Cadance. When Twilight is abandoned at the wedding rehearsal, Jewelius pretends to leave reluctantly, but then he secretly spies on Chrysalis sending Twilight to the underground caverns and reacts by starting to make a plan.
When Twilight and Cadance expose Chrysalis during the wedding ceremony, the Changeling Queen is momentarily very surprised — to the point of asking why — when Jewelius tells her that he sent his assistant Vivian to help the two mares out of the caverns. Right before Twilight shrinks all the Changelings with the spell Jewelius showed her and traps them in a glass jar, the prince gives Chrysalis a Psychotic Smirk. Inside the jar, the miniature Chrysalis tries in vain to say something while pointing at Jewelius. It's not until the 11th chapter that it's revealed that Jewelius and Chrysalis worked together as a couple to take control of Equestria, but he double-crossed her when he decided to become the only ruler of Equestria by making Twilight his pawn.
One of the first hints to Jewelius' plan to marry Twilight and father a legacy through her? He names himself "Holy King Jewelius I" after he speaks to the unconscious Twilight about restoring greatness to Equestria with her.
A Moon and World Apart: Vinyl's explanation of their medical system, including how artificial limbs and other parts won't be forced on a pony, prove prophetic when Rainbow Dash sacrifices a wing while saving ponies' lives during the terrorist attack on the Orion, and is offered a prosthetic replacement afterward.
Pound and Pumpkin Cake's Adventures (and Misadventures) in Potty Training: In chapter "To Snatch a Potty", Pound is said to have a plan to put his twin sister Pumpkin off using her potty, then the next morning, he sleeps in and then later appears to be smiling evilly. It is then revealed that he was the one who got up in the night and stole her potty.
Quite a bit of it is thanks to Rarity's Foresight ability.
Thanks to various conversations between the Guards and their thoughts when the story's from their POV, by the time their true nature and Dark Secret is revealed early on in Act 2, the more attentive readers are probably capable to piecing it all together already.
The retroactive editing throws a bit into Fluttershy's trip to Dragon Turtle Lake in Act 1; when Master is listing recent affairs in Equestria's neighbor states, he offhandedly mentions Chrysalis having recently become Queen, and how she might prove dangerous in the future. Cut ahead to Act 2, where we find out that the Changelings have begun invading Gildesdale as a prelude to invading Equestria.
The Writing on the Wall features sick workers, the eponymous writing on the wall, and even the metallic thorns built to keep people away from the building, though most of it is going to fly over the heads of people not familiar with a specific and obscure building proposal. The "tomb" that Daring Do is investigating is the proposed Yucca Mountain facility for storing radioactive waste. The building was never built because of concerns that something like the story would happen- that despite all our current efforts to warn others away, a far-future society that couldn't read our language and had no knowledge of our symbology would get curious and investigate. The description of the "tomb" is a dead giveaway- the massive thorns and the writing are proposed deterrents for the structure.
Naruto is upset that Tsunade can't use any jutsu to make him remember stuff he forgot due to his amnesia, but she tells him she just wants to protect him from any more harm. Tsunade then notices he's smiling and asks him why he's doing that. Naruto replies that he kinda feels like she's his mother when she's acting all caring like that. Several chapters later, he accepts to become her adopted son.
In Chapter 46, three masked ninja are with a group of captives. One of the masked ninja take a look at one of the women among the captives and is reminded of Kurenai. Several chapters later, it's revealed that this one masked ninja in question is none other than a resurrected Asuma.
Early on in chapter 5 of Advice and Trust, Asuka playfully teases Rei by claiming that she would have a better chance of defeating an angel by making out with one than fighting it in her Eva. Five chapters later, she hooks up with Kaworu.
HERZ: In an early chapter, Shinji mentions that Asuka was feeling quite "frisky" and demanding lately. In the final chapter, Maya revealed that Asuka was pregnant.
The Second Try: When the moment of Asuka and Rei's elevator conversation comes up in chapter 7, Asuka takes the initiative and tells Rei of the advice she got from her in the previous timeline to open her heart to make the EVA move, asking her if she does it herself. Rei replies that she mustn't. Two chapters later we discover why.
Otto's skill at solving word puzzles, as well as his knowledge of word problems and anagrams in general, hints at his major role in the story later on, when he is the only one able to stop Mariana Mag.
In Chapter 4, Olive mentions how she's never solved a puzzle book that never had math in it before, and in Chapter 9, Otto realizes that the reason no Odd Squad agent could solve the case of agents turning into anagrammed objects is because anagrams are related to language, not mathematics. This foreshadows how language as a subject is far outside of the norm of Odd Squad agents, and foreshadows how major of an impact it has in Mariana Mag's Face–Heel Turn.
In My Dream Is Yours, Jamie Jam had visited Todd's garage sale and picked up a copy of How to Work With Difficult People in addition to a couple other things prior to meeting up with Odd Squad. And then Ohlm comes along to stop her, and she realizes that he's going to start being the "difficult people"...
OSMU: Fanfiction Friction: In Chapter 9, Omar receives a premonition from a Fortune Teller about a white-striped boy who is going through a battle that the Mobile Unit has to ensure he doesn't lose at. This hints at another plotline in a couple later chapters, where Todd works as The Mole for the Mobile Unit and tries to stop an Enfant Terrible villain, Basil Valentine, and his two henchwomen Ambrosia and Nectar from uncovering the secret of Odd Squad's Proportional Aging.
Time to Disinfect: When thinking about her bad leg, Mari notes that it could sometimes buckle completely from the pain. A few chapters later that's exactly what happens at the end of her argument with Sunny.
The Dragon That Will Pierce the Heavens has plenty of this about protagonist Hikari's past. From the first chapter, there are hints of her escaping from some sort of troubles, from old bruises to out-of-character overreactions to surprising knowledge. It's not until the Return To Water Seven and Heartfilia Arcs that it's revealed Hikari is a World Noble that ran away from an abusive home, where she was about to be married off to none other than Donquixote Doflamingo as a broodmare.
I Think We'll Be Okay: Kosuke notices a letter on her father's desk with curious words like "owe" and "don't be stupid." Her father dismisses it, and it isn't until after he dies that Kosuke finds out what it was: Marti had racked up a debt to a loan shark and was falling behind on payment.
When Mitsuru is watching TV in Catch Perfect, one of the programs mentions the latest deaths in the Inaba serial murder case, an instance of Five-Second Foreshadowing to the deaths of Hamuko's Investigation Team. After that reveal, Hamuko notes that's been foggy lately, foreshadowing Izanami spreading her fog unimpeded and subsequently bringing about The End of the World as We Know It.
In Chapter 28 of Butterfly Cascade, Akechi tells Akira that "all the world's a stage". Later, Akechi's Palace turns out to be a theatre, with Robin Hood quoting this exchange back at Akira.
Despite what Minato assumes of him, the narration in As The Bells Toll never once calls the Other Side's Tatsuya by name; a big hint towards the fact that he's actually Nyarlathotep trying to manipulate him.
Several locations that the characters later travel to are sometimes mentioned in conversations between other characters.
Early on, Blitz is revealed to know Fire Fang and Ice Fang, but for some reason, he doesn't like using them in battle. His backstory reveals that this is because he accidentally did permanent damage to a Luxio's leg with one of those attacks. Conversations between Blitz and Hercules also hint at other parts of Blitz's backstory, which is fully explained in chapter 22.
A lot suggests that the main villain is not an ordinary Sigilyph. The villain also mentions Cassandra, one of the previous town oracles, a few times. It is later revealed that the main villain is actually an evil spirit currently possessing the Sigilyph, rather than the Sigilyph itself. Chapters 34-40 shows that the spirit was once a Mismagius named Erebos who was corrupted by the dark magic he experimented with and that Cassandra played a major role in how he back then eventually ended up as a Sealed Evil in a Can.
Pokémon Reset Bloodlines has this come up in the fanfic and its expanded universe fairly frequently.
Times two. In chapter 16, Oak hopes that Ash never captures a Grimer or a Muk, since they smell bad and can be very clingy. Not only does Ash (re)capture his Muk upon going to Gringy City, but he also accidentally captures thirty-two Grimer, all of them just as clingy and hug-happy as Muk.
Given that Bloodliners are all Big Eaters, Lara's and Hex's stomachs rumbling alongside Ash's, Misty's, Iris' and Anabel's was an early hint to their status as Bloodliners.
After defeating Janine in Chapter 22, Paul mentally notes that his Raichu's performance was slipping, and considers releasing her if she doesn't improve. In Chapter 27, she gets knocked out by Iris's Excadrill in the Tag Tournament's semifinals, and he makes good on it.
At the beginning of Chapter 28, while exploring the Safari Zone, Misty jokes about Ash finding a Shiny Chansey, and he ends up catching one with his last Safari Ball. She and Anabel also muse about wanting to find an Eevee, and end up encountering one, which takes a liking to the latter.
When Ash receives a Z-Ring without Z-Crystals from Hala and Tapu Koko, he has a vision of canon battles with Z-moves. Of all the ones he saw, only one Z-Move wasn't one that has appeared in the anime at that point Psychium-Z.
Similarly to this, the history lesson via info dump Hala gives in Chapter 24 turned out to be hinting at what would happen ten chapters later.
When exploring the ruins beneath Saffron City, Nightshade comments that Pokemon Tower was thought to have been built by the same civilization. The artifacts in the Tower prove crucial in returning Dan and Missy home.
The phrase "Pokemon are made of stronger stuff than humans" is thrown about a great deal in the early chapters. This foreshadows Missy's survival of the apparently-lethal wound inflicted on her at the story's end.
At one point, Masque responds to Giovanni's directives with a smug "You cannot control a marionette with only one string." This comment, seemingly mere insubordination, actually confirms in a big way that Masque is the real danger and manipulating Giovanni. It even receives a direct Call-Back when Masque reveals his true nature.
Even before knowing that the game he found was hacked, the narrator or Pokémon Strangled Red notices a tear across Charizard's neck on the game package.
Occurs twice in the Portal 2 fanfic Test Of Humanity. First is when Wheatley gets stuck in a garbage chute after trying to find a way to get into the lab and save Chell.. He later gets stuck in an exhaust pipe (he's too fat to fit all the way through) causing it to explode. The second time is when Wheatley is overwhelmed with guilt after watching 2001: A Space Odyssey and begins comparing himself to HAL. During the climax GLaDOS tortures Wheatley by playing the film but replaces HAL's dialog with Wheatley's evil speeches from the games.
Ciel mentions a few times she has an extremely low Aura, and one of the first things noted about her time looping is that Semblances are supposed to only work when you have Aura. Ozpin theorizes that she's holding the bulk of her Aura in reserve, so when she dies she still has enough to send herself back in time. But that also means she has a stockpile, which is being depleted. She's going back less and less each time, and soon will run out.
The "bird strike" that delayed the Manta picking up Penny turns out to have been Qrow, scouting the Atlas airships.
After Roman confronts Raven about Team STRQ just losing a teammate when they lost Summer, Raven quietly says that she "lost more than that". Then comes The Reveal in Chapter 59, and we find out that Raven and Summer were the Official Couple of STRQ.
When Roman comments on the family dynamics of Team STRQ, although the words "mom" and "uncle" are thrown around a lot, the word "dad" is not used at all, not even when describing Taiyang. It's later revealed that while Taiyang is Yang's biological father, it was Summer and Raven that were the girls' mothers, with Tai just being their godfather.
There's some foreshadowing to Ruby being transgender, such as when she's misgendered in the first chapter and later when she's nervous about changing around other girls.
Roman and Neo's backstory is foreshadowed early on when the Malachite twins say he's hiding out after having killed a criminal's son. He and his daughter Neo killed the guy, Augustus, after he raped Neo.
When Ruby comes out to her, Weiss mentions that she wouldn't mind if either of her sisters came out as trans. Many chapters later, Weiss' brother Whitley is revealed. He began transitioning while she was at Beacon.
Qrow being Summer's lover and Ruby's biological father is foreshadowed a few times early on, such as when Ruby gets angry and asks if Summer was a rebound upon learning Yang has a different mother from her.
How Weiss got her facial scar is foreshadowed when she's asked about it and sees Mirror cutting her face with a nail and when she touches her scar after wondering why Blake hurt herself by punching a wall. It's later shown that Weiss scarred herself.
Flam Gush starts off seeming like it might just be romance, but several hints in the first chapter, such as Lina's commentary on knowing about "rolls in the hay", read much more darkly by the end.
The tapestry from Gourry's old home was brought to the inn by his crippled mother.
When Lina hears about Erik's death, she briefly feels as though she should have already known that already.
In By the Fire's Light, the endgame of the six-story series where the world ends is foreshadowed during a brief interlude that touches on the Slender Man's origins in the second story in the arc "The Wanderer of Blazes."
In Robb Returns, Jojen's dreams serve as this - at least, those that have not been fulfilled yet when he tells about them.
Tywin Lannister and Oberyn Martell know that, with the return of magic, someone is bound to attempt to wake up a dragon and cause Summerhall all over again. Viserys Targaryen ends up killing himself and Illyrio Mopatis when he tries to wake up the dragon in the (fake) egg the latter gave him, burning down a third of Mopatis' manse and incidentally causing dragons to reappear after more than a century... under Daenerys' control.
The King Nobody Wanted: Rys Chelsted having clubbed feet that keep him from walking without a cane is subtly foreshadowed on several occasions. His wife comments that he dislikes dancing, Rys tells Davos that he could never dream of being a knight as a boy, only of living in a world “where all men could stand” (although it initially sounds like he is talking about a system of society based on merit instead of birth, and that may be a double-meaning comment). He has trouble restraining his anger for a moment when Cersei remembers that King Aerys compared him to a frog. He sounds bitter when telling Stannis to be wary of clergymen, given how they claim they can heal physical afflictions but usually fail to.
Frequent in the Sonic X fanfic Don't Keep Your Distance. These hints range from the minor, like seeing an old friend again after she is mentioned in passing in conversation, to the first major attack by Dr. Eggman being foreshadowed by a radio broadcast that isn't quite intelligible.
The rewritten Episode 69 of Sonic X: Dark Chaos focuses on Sonic and friends being caught in the middle of a religious conflict between Marmolim Christians and the Marmolims who worship Maledict. The satanic Marmolims initially revere Sonic as a literal messiah sent by Maledict to save them from the Shroud outside their city, while the Christians accuse him of being The Antichrist and a spawn of the devil. Episode 75 reveals that both of them are more correctthan they could ever know.
Also from Episode 69, there's a scene (taken from the original series) where Cosmo receives her fortune from a Marmolim seer, who says that her hate will bring suffering and death to those close to her. The previews of the sequel make this a form of retroactive foreshadowing - Cosmo snaps from the trauma, jumps straight through the Moral Event Horizon, and becomes a Woobie, Destroyer of Worlds.
Cosmo takes Venus' demon-powered scythe from Tsali after he is beaten in Episode 73. In the sequel, Cosmo's actions parallel Venus' mistakes almost to a tee - with tragic consequences.
Every time Fang is defeated, he leaves with the Marvelous Queen already equipped with the weapon he'll use against the heroes in the next battle.
In a cutscene on Egg Zeppelin Zone, Sonic and Tails catch Robotnik making a Dark Emerald copy using the Chaos Emerald he stole, which he uses on them in Atomic Destroyer Act 2 and how Metal Sonic transforms, by making Dark Emerald copies.
In a meta-sense, Sonic & Tails can sometimes come across walls that look like they should be destructible, yet aren't, hinting at Knuckles's playable status before he is effectively unlocked.
One particular clue to Knuckles really being Metal Sonic in disguise is his boss theme. While it's a remix of Knuckles's theme from the Sonic 3 prototype and PC Collection, it contains some off-key but recognizable riffs from JP Bad Future Stardust Speedway, which is now strongly considered to be connected to Metal Sonic.
Another clue is in his boss fight in Sunset Park Act 1. When Knuckles dashes, he gives off a yellow aura when he usually gives off a red aura in other games. However, Metal Sonic usually gives off a yellow aura when dashing in other games…
Yet another hint that Knuckles is really still on your side is that when his face appears in the roulette Bonus Stages, it will have a positive effect (giving you rings), and when you run past the signpost and he appears on it, you will be awarded with an extra life.
Even the fact that Knuckles initially doesn't appear on the title screen, whereas he did in the original game, is an indicator that something isn't quite right. Indeed, when Knuckles' true role in the story is revealed by finishing Sonic and Tails' campaign, you can occasionally see him hiding in the title screen from that point on.
Inkopolis Chaos: Foreshadowing is absolutely everywhere. In the first story, it’s frequently foreshadowed that Samuel and Natalie will end up together, and even outright confirmed in some of the stories tags. The first story even foreshadows some of the third story when James and Jess argue with Scarlet, and only going with her plan either out of fear or boredom, which foreshadows them abandoning her in the future. More foreshadowing in the first story to the third story is when Ruby says she doesn’t deserve to live, which foreshadows her sacrifice in the third story. The second story foreshadows Cyalux’s secret villainy multiple times. The first time is when he sneakily puts a golden egg in his bag during a salmon run shift. The second time is when he says he will speak to Melissa, but when Melissa talks to Sylvia, she doesn’t mention him speaking to her. There’s also some foreshadowing of his brother, as he asks if he was the only one who got on with his brother. The third story also has some foreshadowing, with Adelyte joking about Luke, Summer and Melissa being in a threesome, foreshadowing that Luke and Summer would end up together. There is also more foreshadowing of Ruby’s death, when Marie asks the agents to come back in one piece, and Ruby promises she would, even though Ruby sacrifices herself moments later.
The Lady of the Garden has Jack O'Neill snaked up, and he almost immediately starts to display weird behaviour such as protectiveness towards the Goa'uld, painting his nails and assuring his body is only his. Daniel has a "Eureka!" Moment when he looks some writings by the Goa'uld which made use of feminine speech patterns — the Goa'uld is actually female, and O'Neill was only trying to comfort a frightened little girl who really didn't enjoy being stuck into a male body.
Red Sadie The Eye of the Storm: Before Clancy leaves her office, Nanefua notes that despite being her dad, Sadie looks nothing like him. It's later revealed that he isn't actually her father.
Clash of the Elements: Hints of future plot events are thrown out quite often in Part 1 alone. A few examples include:
Rosalina's Big Damn Heroes moment, were it not easy enough to figure out before, had the clearest hint given at the end of Chapter 35 with the words: "shadow of an observatory"
Likewise, Mario destroying Joe Dark's sword with his star energy is hinted at during previous battles against him, where star energy was proven to be capable of dealing critical damage to beings consumed by darkness.
This hint is a bit of a stretch towards the end result, but The Genesis Samurais' souls going into Alex's body was more than likely foreshadowed by this line:
"Though his body may be weak, his soul still lives. And as long as that's alive, then he shall live as well"
In Chapter 4 of The Brother's Grimm, Bernard states his belief that the only way for him to recover from the trauma he feels over being the one to accidentally murder Seymour Murphy's father would be to save a life. In the next and last chapter, that's exactly what he does.
The reference to 19 (instead of 20) spectators in the Peanut Gallery during the final challenge and the flowers on the table hint at the nature of the tragedy that drives the story.
The description of Chef Hatchet’s attempts to save his mortally wounded patient foreshadow that he will fail.
Total Drama What If Series: In the first episode, Brick noticed Amy abusing Sammy and noted in the Confessional that sisters shouldn't treat each other badly. Cut to a season later, and Brick and Sammy are a couple.
When Syaoran nearly gets run over by a car in Shatterheart, he notes that a car accident would be a relatively quick death and he could have died in worse ways, like being tortured or impaled by a sword. He gets kidnapped and tortured in chapter 41 and rammed through his clone's sword in chapter 144.
Sakura encourages Kurogane to confess his romantic feeling to whom he's in love with, warning that if he doesn't, he will regret not doing so when they inevitably have to move on since Kurogane intends to return to Suwa. Kurogane confesses his love for Syaoran after they're nearly killed by Fai and decides to continue traveling with him instead of returning to Suwa.
Once in a while, both Co-op Mode and its companion fic A Bug In The Game have interludes that act as like this. For example, Fortuna's interlude ended up foreshadowing Armsmaster being sabotaged into tranquilizing James as well as Coil's interlude hinting an earlier confrontation with the villain.
AWE Arcadia Bay (Rogue_Demon): Jesse crossing paths with Max and Chloe are foreshadowed when she hallucinates a blue-butterfly (an animal that represented Chloe in Life Is Strange) after she defeats The Monolith.
Black Sky has Blaise complaining about Dorea's tendencies to rush headfirst into danger, dramatically claiming she would marry a dragon rather than fleeing for her life if she was a fairy tale princess. Her future husband is not a dragon, but he's quite ill-tempered, selfish and inclined to throw fireballs at what displeases him. Also, he's a real prince, making Dorea royalty by marriage.
Federico loses common sense when someone twirls a skirt in front his nose, leading Squalo to wonder when some vengeful brother or father will try to butcher him. Fast-forward to the year he truly falls for Aria Giglio Nero and...
In Breath of the Wild, which exists in a greater universe crossing over MCU, DCEU, and various Nintendo characters, there a lots of hints early on that build to greater reveals.
When Link is in the Trial of the Wolf, he notes that the monsters there have different features to that of the ones in the overworld, in that their eye colors aren't the same. This is the first hint that the monsters would Heel–Face Turn after the defeat of Dark Beast Ganon purged them of the Malice that had infected them and turned them aggressive...which has the ripple effect of changing their eye colors.
Link consistently has dreams of the Hero's Shade, who adopts the form of a wolf alongside with numerous other wolves with unique features. This is because wolves are the Hero of Hyrule's animal motif, as he was always destined to wield the Wolf Spirit of Courage.
A pink sand seal named Kali shows incredible affection towards Link right off the bat, and another character in their mind compares the loyalty to the kind a horse shows its master. It's the first hint that Kali is actually the reincarnation of Epona who remembers her past lives and thus recognizes Link as her true master.
Child of the Storm uses these frequently, often through the slyest of references and asides. And then in the finale, pretty much every single one of the manyChekhovs Guns fires at once. It is possibly for this reason that the finale covers four chapters - and that's not counting the two chapter epilogue.
Code Geass: Paladins of Voltron: When Allura watches Suzaku and Lelouch arguing about how Britannia should be opposed, she briefly feels as though she is watching her father argue with 'someone else'. It's implied she's thinking about her father and Zarkon talking about whether or not they should use the Quintessence.
In The God Empress of Ponykind, Discord mentions that he saved someone in the Warp during his first fight with Celestia, but doesn't elaborate further. During the Final Battle with Nightmare Moon, it turns out to be the redeemedspirit of Horus, who helps Luna break free of The Corruption long enough for Celestia to use the Elements of Harmony.
When Church and Twilight talk to Sheila/FILSS in I Against I, Me Against You, she refers to Church as Director before either of them have any idea what Church really is.
A few chapters later, Church explains why he joined the army in the first place.
Church: Honestly? It was because of Tex. She joined the army and left me without so much as a goodbye, so I decided to go after her. It was either that or med school. And really, can you picture that? Doctor Leonard Church?
Last Child of Krypton: In chapter 3 Asuka moved so fast that even Shinji -who is Superman- was surprised. In chapter 12 she slapped Shinji and again he got stunned by her speed and surprised because her slap actually stung (even though he is nearly invulnerable). Then she tackled him before kissing him. A few chapters later it was revealed her mother was an Amazon, so her greater-than-average strength and speed made sense.
The chapter "A Limitless Chest of Tales" in Manehattan's Lone Guardian sees Leviathan caught in an illusion generated by Salamandra's heartsong, showing that even as a Reploid her mind can be influenced by such things. This serves to foreshadow the antagonistic Illudere catching her with a similar trick in "Curveball on the Outside Corner", dozens of chapters later.
In Chapter 15 of Origin Story, Alex Harris jokes about how "There's never a gym bag full of hundred dollar bills around when you need one." Her girlfriend, Louise, then responds that, "if we ever win the lottery, we're going to have to remember to always keep a gym bag full of money handy.” In Chapter 19 — after they've robbed Norman Osborn — its revealed they keep a dufflebag full of hundred dollar bills in the trunk of their car for emergencies.
Bloom is led to the point where she gets forcibly teleported to Outland by a quickly moving shadow.
Domino's Elder stating that newborn Altalune is not fated to become Domino's future queen indicates that this role will be filled by her younger sister Trisha, whose conception we learn of in the next chapter.
"Chapter 04": Bloom discovers that she's pregnant with Trisha through her blood pact with Galadwen, meaning that her youngest daughter is also bound to Elune's chosen.
Pokémon Crossing: Benedict's a closeted transgender girl. This is foreshadowed by several throwaway lines, including mentions of gender dysphoria and several dreams about being a girl. Chapter 42 confirms this and has "him" come out as Holly.
Before Discord reveals himself as one of the Big Bads of Sonic Generations: Friendship Is Timeless , he has made his presence known at several points in the fanfic. The Author's Notes in The Reveal chapter should explain everything, because, really, there's a lot.
In The Story to End All Stories, Penny Pringle notes that the person responsible for releasing the Nothing must be someone with true cunning. It turns out to be Chuck Cunningham from Happy Days.
In Chapter One, Steven drew a detailed star on the beach, which sadly gets washed away. Later, in Chapter Fifteen, a star demon named Gabriel appears and possesses Steven.
In one nightmare caused by Bill in Chapter Two, it depicts Lapis being caught by a net and waterfalls spilling through her eyes and mouth, like in "Chille Tid". Steven then expresses worry that she may be trapped somewhere. In Chapter Forty, it's revealed she's become a prisoner on Jasper's ship, and is not happy about it.
The last nightmare of the chapter has Steven exploring the ravaged Beach City. In it, he also finds Lars and Sadie dead. In fact, they are the first people he finds. Now, who are the first people who later anger Bill in the story?
In the same nightmare, amongst all the shattered-into-powder Crystal Gems there is a dark blue and also a green mixed in. Hmm...SpoilerThis foreshadows Lapis's and Peridot's introduction.
While cleaning up the picnic in Chapter Seven, Sadie ponders about Bill's "ungrateful jerk" outburst back in Chapter Five, wondering, albeit doubtfully, if there was a reason for it. There is. Bill was abused by his parents long ago and was thus driven byenvy, and furthermore exasperated by Sadie having taken her mom and the stuff she did for her for granted.
Connie seems to gravitate towards the mention of Gravity Falls in Chapter Ten, certain she heard about it a time ago, but is unable to remember, much to her dismay. Fast forward to Chapter Twenty-Three, and it's found out that her memory of it had gotten erased by the Blind Eye. And they probably got her family too, and told them to leave...
Pyronica always chose to go left. Seems funny and like a quirk, yeah. But with what do people usually associate with that direction? That's right. Pyronica later betrays Bill, revealing that she was on Gabriel's side the entire time.
In Chapter Thirty, Bill indirectly tells Steven that in his dimension, stars surpass triangles in the hierarchy. Later, Steven begins to have thoughts that aren't his own. They say, "Lowly triangle. Mighty star." And Steven himself is a star; he noted that himself. And the kid was already more powerful than Bill, due tocircumstances.
Throughout almost the entire story, there are hints pointing towards a certain... "trait" Bill has buried deep inside, and even blatant digs are made at the issue. He turns out to suffer from severe, but well-hidden, depression due to his past actions, his past in general, and his newfound empathy makes it no better and in fact caused it all. Ultimately, in Chapter Forty-Four, he tries taking his life. Fortunately, Steven talks him down.
, Chilli acts unusually tired, and she also coughs the morning after the hot sauce was bit. This foreshadows that the vampires don't exist and it was All Just a Prank cooked up by Chilli, who was the one biting the food in the night.