Chris Hemsworth Thor helmet face paint

The Marvel Cinematic Universe has been expanding ever since 2008’s Iron Man; Tony Stark’s origin story built the groundwork for the MCU as we know it today, and fans have continued to receive a steady stream of cool, new superhero movies — and with Disney+ now in the mix, a host of MCU-themed TV shows is entering the fray. Apart from the sheer amount of story the MCU’s first three phases include, the movies are also somewhat famous for the amazing amount of neat Easter eggs they contain. Since most every Marvel superhero has decades of comic book history behind them by the time they make it to the big screen, the filmmakers invariably have a treasure trove of comics history from which to draw — and to which they can make subtle reference.

Filmmakers have been more than happy to drop stealthy nods to the respective source material, to the point that any serious attempt to keep track of every Easter egg in the MCU would require a massive spreadsheet and the kind of dedication that’s basically a superpower in itself. After all, the list of WandaVision Easter eggs is already growing and the show just ended. As cool as all these neat surprises some MCU properties contain are, some movies are devilishly creative in hiding them — and as a result, a handful of super-cool Marvel Easter eggs weren’t discovered until years later.

Obadiah Stane’s musical foreshadowing in Iron Man

Jeff Bridges Obadiah Stane piano drink

Iron Man was the movie that made the MCU possible, so it makes sense that it featured some of those cool Easter eggs for which the mega-franchise is so famous. The hidden details in Iron Man are many, but that doesn’t mean they were all easy to find. In fact, according to Digital Spy, one particular Easter egg took fans a good decade to discover. Iron Man’s villain, Obadiah Stane (Jeff Bridges), starts out as a fairly jovial presence, who’s propelled forward by Bridges’ affable Dude charisma that even manages to shine through Stane’s immaculate suits and chrome dome. The reality, of course, is much different, as Stark Industries’ second-in-command is actually responsible for Tony Stark’s (Robert Downey Jr.) kidnapping by the Ten Rings terrorist organization and he eventually dons the hulking Iron Monger armor to give Tony his first taste of supervillain combat.

In 2018, Reddit user HellotoHorse noticed that Stane actually foreshadows his true intentions fairly early on in the movie, by sitting behind a grand piano and playing a nice piano tune. The thing is, the ditty isn’t quite as unassuming as you’d expect; the man behind the composition is actually Antonio Salieri, a 18th century composer who some people believe killed the legendary Wolfgang Amadeus Mozart. In reality, this probably didn’t happen, but this version — as told in the popular 1984 movie, Amadeus – does mirror Stane’s Iron Man arc eerily well. After all, both Stane and Salieri (F. Murray Abraham) are older, less brilliant talents who envy the prestige of younger, celebrated geniuses, and eventually start plotting their respective downfalls.

Guardians of the Galaxy still guards major secrets

James Gunn’s Guardians of the Galaxy Vol. 1 is a treasure trove of hidden references, and, for years, the director has guarded them so jealously that he even refused to reveal a major Easter egg to star Chris Pratt. Though the movie came out in 2014, there may still be secrets just waiting to be discovered. Gunn has teased for years that a massive discovery has gone unnoticed, and may very well still be, though in April 2020, the director did admit that "a large part" of the final major Guardians of the Galaxy Easter egg had been discovered — some think that it might hint that Peter Quill’s (Pratt) mother, Meredith (Laura Haddock), is actually a cosmic force known as Eternity.

The jury is still out on whether that’s actually the case, but fans have certainly received their money’s worth of Easter eggs from the movie. In 2018 — four years after Guardians of the Galaxy Vol. 1 came out — Gunn confirmed a hitherto undiscovered Easter egg, in which Stan Lee’s cameo scene subtly features Lee’s famous catchphrase, "Excelsior," written in Skrull language. As recently as February 2021, the director took to Twitter to shoot down a theory that an image of Peter’s father, Ego (Kurt Russell), was hiding in Meredith’s brain scans — and casually revealed that the brain scans originally contained another Easter egg, which may or may not be in the final cut. And so the hunt continues.

Doctor Strange’s stealthy Groundhog Day reference

On February 2, 2018, Doctor Strange director Scott Derrickson was a happy man. As he revealed on Twitter, someone had finally managed to uncover an Easter egg that was evidently quite dear to him. "I’ve waited two years for somebody to notice this," Derrickson wrote as he retweeted the discovery.

Twitter user @TimDLydon noticed the Easter egg, which reveals that one of the most dramatic events of the movie happens on a very particular date. "Fun fact: the car crash in Doctor Strange is actually set on Groundhog Day," the user wrote, along with an image of Stephen Strange’s (Benedict Cumberbatch) expensive watch that reveals the date of the accident is indeed February 2. Groundhog Day is, of course, a very real day, but also a legendary 1993 time loop comedy starring the equally legendary Bill Murray. The nod is more than just a cool, stealthy allusion to the comedy classic — it’s also a subtle hint at the good doctor’s future. After all, Doctor Strange eventually wins his seemingly hopeless face-off against the mighty Dormammu by trapping the powerful villain in a Groundhog Day-style time loop, dooming it to live their confrontation over and over again until it becomes frustrated and gives up.

Thor’s fake ID features a familiar image

Thor came out in 2011, an innocent time when the MCU could surprise fans with now-common crossover twists like "Hey, isn’t that Agent Coulson (Clark Gregg) from Iron Man?" and "Whoa, was that a Hawkeye (Jeremy Renner) cameo?" That’s not to say that the movie doesn’t have its share of Easter eggs, though. For instance, when Dr. Selvig (Stellan Skarsgård) makes Thor (Chris Hemsworth) a fake ID, he decides to call the God of Thunder Dr. Donald Blake — a character who’s basically Thor’s secret identity in the comics.

However, Comicbook.com notes that it took fans until 2019 to notice the other surprise in the ID card. Earlier in the movie, the characters have breakfast at a diner, and Darcy (Kat Dennings) decides to snap a picture of Thor with her mobile phone. When you compare the smile Thor gives her to the one in the ID, it turns out that this seeming throwaway sequence actually showed us the very moment they got the picture for the ID. A small surprise like this is hardly earth-shattering, but it does show an impressive attention to detail from both fans and filmmakers alike.

Avengers: Endgame sneaks in a stealthy reference to Tony Stark’s fate

2019’s Avengers: Endgame ended the Thanos (Josh Brolin) cycle of MCU with a bang, and the movie is full of pause-worthy moments. Apart from the amazing action and moving plot twists, the Russo brothers crammed the movie so full of references and cool little surprises that you probably missed a whole lot of Avengers: Endgame Easter eggs while you were busy picking your jaw from the floor. Who can tell what secrets the movie is still hiding? In January 2021, fans managed to unearth another seemingly obvious yet evidently heretofore undiscovered Easter egg in the movie (via Inverse). Before the movie even came out, Twitter user @janalgme tweeted: "Found a mistake in Avengers: Endgame trailer — Thanos broke right half of Tony’s Helmet in Infinity War, while trailer shows Left half of helmet is broken. How did it happen???"

Turns out, this may not have been a mistake at all. Instead, fans have now noted that the damage to the helmet’s right side is eerily similar to the facial injuries Tony Stark sustains after defeating Thanos’ forces with a snap of his nanotech Infinity Gauntlet. Talk about sneaky foreshadowing!