Foreshadowing / Us 2019

aka: Us

• The movie opens with a scroll that explains there are thousands of miles of abandoned tunnels beneath the continental United States, many with no apparent purpose. This seems like an odd non-sequitur that has nothing to do with the plot, until the climax reveals that the Tethered have been kept imprisoned in all of those tunnels for generations.
• During the opening, when she gets lost in the mirror maze, Adelaide starts whistling The Itsy Bitsy Spider to herself, before hearing the Tethered Adelaide whistle tunelessly back. Later on, Red makes her first adult appearance in the movie whistling said song while walking up to Adelaide's summer house. And then later whistles it again moments before Adelaide strangles her to death. It turns out that Red is the real Adelaide.
• Speaking of "tuneless" (and credit for this one goes to Austin Walker), as "I Got Five On It" plays", Adelaide tries to teach Jason to snap in time to the song. The thing is, she's snapping out of time, hitting the ones and threes instead of the twos and fours, an early sign she's not completely socially adjusted. This plays into the final fight between Red and Adelaide; Red gracefully dances around Adelaide, dodging and attacking, and Adelaide is "offbeat" the entire fight and can't keep up until she gets a lucky shot in.
• In a flashback, Adelaide's refusal to talk after the beach incident makes much more sense after we learn that she's actually a clone who had never learned how to speak. Additionally, Adelaide gives a wide-eyed look of horror upon meeting her Tethered counterpart, which carries over well into her adulthood as "Red".
• Adelaide's mother told her psychiatrist that, after the incident at Santa Cruz, all she wanted is for her daughter to be back again. By the end, we learn that her daughter literally never came back from Santa Cruz.
• When Adelaide tells Gabe about when she met her doppelganger, she says she went down to the beach alone, she doesn't know why she did it, she just did. She really doesn't know why she did it, since she isn't the original Adelaide who went down to the beach. She may also have been referring to the Psychic Link between her and the real Adelaide compelling her to mimick the original in going to the Fun House without knowing why.
• When the other Tethered break into their home, they are focused on just entering and cornering the family, but when Red makes her entrance she takes her time to observe things the family owns. As she does this, she stops at the fireplace to look at a painting as if it's familiar to her. This looks like it's establishing Red as a leader and different from the other Tethered, but it makes a lot more sense after The Reveal. Of course someone who hasn't been in their old home for a long time or has lost certain comforts would be interested in the changes they see and the old pictures and photos that are still hanging up.
• Red is the only doppelganger who can actually talk for the entire movie, and is unusually cultured, making references to both God and the The Goonies: "Now it's our time, it's our time up there!" However, her voice is very rough and scratchy, especially when she first starts talking, as though she hasn't used it in a long time. She is actually the real Adelaide who was trapped underground in place of and by doppelganger Adelaide. Red knows how to talk because she learned to talk before being trapped underground, but none of the other Tethered can speak outside of animalistic grunts, so her ability waned. In addition, the doppelganger Adelaide choked her when she was kidnapped, which would have damaged her throat. As for the references, during the Hands Across America commercial a VHS copy of the The Goonies can be seen next to the TV Adelaide was presumably watching, and in the flashbacks Adelaide's mother makes references to God.
• At the dining room table as the family is settling in, Gabe tells a "Knock Knock" Joke:
  Gabe: Knock, knock.
  Zora: Who's there?
  Gabe: You.
  Jason: You who?
  Gabe: Yoo-hoo! Open up the do-o-or!
  • On its face, it's just a throwaway snippet of dialogue that reinforces Gabe's penchant for corny dad humor. But it's outright chilling in view of the events to follow. "Who's there?" "You. Open the door." is a pretty accurate summary of what happens at the Wilsons' house after nightfall.
  • Another example with Gabe and his bad jokes. When Adelaide tells Gabe about how she met her other self while in the house of mirrors and is afraid she will come after her again, because she still senses her presence, Gabe tries to cheer her up by joking that him being a big guy means he could beat her up, so if the evil clone showed up he would beat her up too. After she gives him a hostile look instead, he admittedly regrets it, because the joke came off like a domestic violence threat, but the ending makes it clear that Adelaide wasn't offended by possible domestic violence, but the fact she is the clone and took Gabe's joke as a direct threat. Another way the ending adds context to Adelaide's reception of the joke is that she would be aware that the real Adelaide might not be coming alone, but could have a version of Gabe with her. She wouldn’t be able to rely on Gabe protecting her because he would have to fight his own copy.
• During the family's trip to Santa Cruz, Zora tries to start a conversation with the conspiracy theory of the government adding fluoride to the water systems to control people's minds. While the government really did try to achieve the same goal, it was instead through a failed cloning experiment.
• When Abraham has Gabe trapped on the boat, he starts howling into the sky. He actually gets similar howls back as a response before it's formally established that the Wilsons aren't the only family with doppelgangers on the loose.
• When Red tells the story of the lives of Adelaide and herself during their first meeting, and how horrible Red had it compared to Adelaide, Adelaide starts crying. With the reveal that Adelaide was originally one of the doppelgangers who switched places with Red, who was the original Adelaide, one has to wonder if those were tears of guilt for what she had done, or tears at the memories of her early life as a Tethered underground coming back and the idea that Red's life would've happened to her if she hadn't escaped.
• At first, Adelaide's insistence on comforting the Tethered children as they die might seem like simple motherly concern for the ones who look like her own children. But since Adelaide is actually a Tethered, she feels empathy for her kin in spite of herself.
• Somewhat doubling as Fridge Brilliance, the Thriller t-shirt that Adelaide's father wins for her back in 1986 is a massive clue in to the film's twist, as said video featured Michael Jackson at the end revealing himself to the audience as a demon the entire time, similar to how Adelaide has been a Tethered the entire time.
• Likewise, one of the first scenes is of the Hands Across America commercial. Right next to it is a VHS copy of C.H.U.D. a film about an illegal subterranean government experiment that the government loses control over and which wreaks havoc on the citizens above.
• Adelaide turns into a downright feral Mama Bear when fighting to protect her family. It later comes out that she's a Tethered herself.
• During the whole ordeal, Adelaide is wearing white, and over time it gets drenched with blood, much like the red jumpsuits the Tethered wear.
• Kitty is talking at Adelaide about her failed acting career and cosmetic surgery when Adelaide says she's not good at talking. At the time, this seems like her trying to politely excuse her disinterest in what Kitty is saying, but this gains extra meaning when we learn that she never spoke a word for the first ten years of her life when she was living as one of the Tethered deep underground.
• Kitty's Tethered is coldly efficient, just like her family, yet she doesn't kill Adelaide. It's because she may know this Adelaide is actually a fellow Tethered, or may have been under Red's orders not to harm Adelaide so she could exact her own revenge.
• When the Tethered first show up, Adelaide immediately calls the police. She is told it will take 14 minutes for them to get there, an excessive response time outside of very high crime areas, and especially for a wealthy and mostly white beach town, and later they're outright put on hold. This is the big indication that what's happening to the Wilsons and Tylers is happening on a much, much bigger scale.
• Adelaide takes up a dropped pair of the golden scissors the Tethered were wielding to fight off one of the Tethered twins, and then immediately flings them away when she's done. This foreshadows how she will later be revealed as a Tethered who has already broken the Psychic Link compelling her to follow the original Adelaide's actions.
• The therapist explains to Adelaide's parents that trauma can render someone mute. After Adelaide rescues Jason from the locker, he refuses to speak, only mumbling. Being kidnapped, seeing his mother kill another person and laugh about it, and realizing she was a Tethered the whole time was traumatizing enough to render an already 'weird' boy mute.
• On the beach, someone throws a red Frisbee that lands on directly on one of the blue circles on Adelaide's beach towel. Adelaide picks it up, revealing the blue circle underneath, and seems disturbed by this. At the end of the film, we find out she replaced the original Adelaide, much like the red Frisbee replaced the blue circle on the towel.
• Jason wears a Wolfman mask, while Pluto wears a human mask, albeit a very odd one. Pluto acts like a dog, Jason acts like a weird human.
• The final fight has Red telling Adelaide, "If not for you, I would never have danced at all." Kinda weird for a Tethered to tell their counterpart, since they wouldn't have existed at all if the original didn't first, but the ending reveals "Red" is actually the original Adelaide. Her parents only had their "daughter" put in ballet after the Tethered Adelaide replaced her, and Red (the original Adelaide) only learned to dance through their Psychic Link. If the Tethered Adelaide didn't exist, Adelaide's parents indeed would've never needed to bring her to a therapist or put her in dancing classes.
• During the Wilsons' visit to Santa Cruz, Jason sees a man standing perfectly still with his arms outstretched, one of his hands dripping with blood. Earlier, the family saw the Jeremiah 11:11 guy being taken away in an ambulance covered in blood. The guy on the beach is J11 Guy's Tethered; having successfully killed his original, he is now taking up his place in the "Hands across America" human chain seen later in the film.