Foreshadowing / Spider-Man: Into the Spider-Verse

• As the Peter Parker of Miles' universe goes over his back-story at the start of the film, he has distinctly blond hair and blue eyes. In addition, it shows Blond Peter doing the infamous dance scene from Spider-Man 3 but doing it in full costume instead of his street clothes. These, plus additional altered details — MJ being the one upside-down during the kiss; Spidey's reaction when Doctor Octopus throws a car at his head in Spider-Man 2 — let the audience know that this universe isn't exactly the one we're familiar with.
• During Miles' walk to Brooklyn Visions at the start, one of his friends mentions an earthquake that Miles had slept through. A few days later, after Kingpin has run his super-collider, there's mention of another earthquake. This indicates that he's run the super-collider at least once before Spider-Man's intervention, explaining the origins of the "glitching" spider that gives Miles his powers.
• The cover of Miles's copy of Great Expectations features Pip being grabbed by Magwitch in a cemetery, foreshadowing Miles and Peter B's first encounter in a cemetery later on.
• When the spider that will bite Miles is crawling over the spray cans, its color shifts to match the lids it is on, foreshadowing Miles' power to turn invisible.
• When Miles accidentally starts sticking to Gwen's hair with his new powers and can't unstick, she tells him that he needs to relax. It's the same advice that Peter B. gives him later. That along with her green ballet shoes and expertly executed judo-throw clue you in that Gwen is an alternate universe Spider-person who is a lot tougher than she looks.
• After Miles bumps into Gwen at Visions Academy, he notes that she's new here and that they both "got that in common." Gwen agrees, noting "Yeah. That's one thing." We later learn Gwen had been stalking Miles and has spider-powers like him.
• Aaron mentions he worked on a recent engineering job near the subway. This foreshadows his involvement in Fisk's Super-Collider project, being constructed just a few tunnels away.
• When Miles flees in a panic from the Collider with Prowler hot on his heels, he passes by the mural he painted with Aaron in the tunnels earlier, the camera giving it a Meaningful Look, as a subtle hint as to who his purser is. A brief P.O.V. Shot from Prowler has him using thermal goggles built into his mask to keep track of Miles in the darkness, able to make out his moving silhouette to chase down. As shown at Aunt May's house, Aaron's reaction would have been very different if he'd been able to make out the unmasked Miles he was chasing down.
• When gearing up to infiltrate the Alchemax lab, Miles tries to add a Superman-esque cape to his hero costume, defending his choice to Peter B that he thinks it looks cool. Amongst all of Kingpin's enforcers, the only one who wears a Badass Cape is the Prowler, showing that it's a Shared Family Quirk.
• Two for the "Bicycle Lady": during the video shown in Miles' class, we can see early on that her name is "Olivia O-", with the majority of her last name blocked by Miles. Couple that with her octagonal glasses frames, and the aforementioned tentacles seen in her lab, and an eagle-eyed viewer can easily guess her identity early on.
• The inclusion of Alchemax, instead of more well-known corporations of the Spider-Man mythos like Oscorp or Roxxon, teases the appearance of Miguel O'Hara (aka Spider-Man 2099) in the post-credits scene.
• Sneaking into Liv's office, Miles knocks a model of the supercollider offscreen, breaking it.
• Sharp-eyed viewers will notice how The Prowler and Uncle Aaron share the same distinctively tall, lanky silhouette. Additionally, the scene in his apartment with Miles shows that Uncle Aaron literally has a painting of a panther with the word PROWLER above his couch and he's wearing a t-shirt from the Brooklyn Muay Thai club with a panther on it. Also, after Prowler enters the film, Uncle Aaron becomes incommunicado with all attempts to reach him getting his voice mail stating "I'll be out of town for a few days."
  • While Peter is "teaching" Miles how to web-swing, Miles complains that "I run better than I swing!" When Miles finally takes the Spider-Man identity for his own, his web-swinging incorporates aspects of Le Parkour to create a sort of webbing-assisted free-running.
• Several examples of foreshadowing set up in this film and paying off in Across:
  • When Miles meets his world's Spider-Man, his Spider-Sense is initially colored purple and green before transitioning to red and blue. The second movie reveals that the spider that bit Miles came from another universe, Earth-42, in which he has taken the mantle of The Prowler. His Spider-Sense changing colors symbolizes that him meeting Spider-Man is what diverted him from the path of villainy he was destined to head down.
  • Blonde Peter tells Miles that the only thing standing between oblivion and stability is him. Even as he takes up the mantle of Spider-Man and protects his universe, the second movie reveals that the very spider that gave him his powers was transported from a universe where Miles was meant to be Spider-Man, robbing the universe from him and making it into a Crapsack World.
  • During the sequence when Miles gets his superpowers, the radioactive spider was glitching and labelled as Alchemax 42. In Across, it pays off as it's revealed that the spider actually came from Earth-42 (and was glitching because it came from another universe), and it was a result of the Alchemax experiments as indeed, their former scientist Jonathan Ohnn said that he was working behind the experiments when he accidentally brought the spider over to Miles's universe.