The new Spider-Man: Homecoming trailer has an Iron Man 3 Easter Egg.
Twitter user @LetsRabbit points out a scene in the Spider-Man: Homecoming trailer features Peter Parker wearing the same t-shirt as Gwyneth Paltrow's Pepper Potts from Iron Man 3. While that sounds a little creepy, the t-shirt features a science joke, so it makes sense for Peter to wear one, and the t-shirt is actually real as well. The joke reads: "I lost an electron. Are you positive?" (via screen rant)
"Spider-Man: Homecoming" has a July 7, 2017 release directed by Jon Watts starring Tom Holland, Zendaya, Michael Keaton, Donald Glover, Jacob Batalon, Laura Harrier, Tony Revolori, Tyne Daly, Bokeem Woodbine, with Marisa Tomei, and Robert Downey Jr.
A young Peter Parker/Spider-Man (Tom Holland), who made his sensational debut in Captain America: Civil War, begins to navigate his newfound identity as the web-slinging super hero in Spider-Man: Homecoming. Thrilled by his experience with the Avengers, Peter returns home, where he lives with his Aunt May (Marisa Tomei), under the watchful eye of his new mentor Tony Stark (Robert Downey, Jr.). Peter tries to fall back into his normal daily routine – distracted by thoughts of proving himself to be more than just your friendly neighborhood Spider-Man – but when the Vulture (Michael Keaton) emerges as a new villain, everything that Peter holds most important will be threatened.