What was the first Easter Egg to appear in a Marvel Cinematic Universe movie?
Looking for answers that are confirmed by the writers/directors/etc. to be Easter Eggs.
The first film in the MCU, Iron Man, has several Easter Eggs in it, such as Roxxon Corp, The Ten Rings and Rhodey's ringtone being the theme song for the 1966 Iron Man cartoon. These are all obviously "meant" Easter Eggs but I can't find them to be "officially confirmed" anywhere. However, the Nick Fury post-credits scene has been officially confirmed as an Easter Egg.
Favreau: When we wanted to bring Nick Fury in, we thought it would be really fun to reach out to Sam Jackson because he was the person the character was based on in the Ultimates.
Feige: Even though the notion of The Avengers came up at that Comic-Con—how could it not—the goal for 2008 was deliver two movies that we hope are profitable so we can do it again. It wasn’t sow the seeds of a big universe. That’s why we put Sam Jackson at the end, the very, very end of the credits, because we thought it would be fun. We thought it would be cool to have Sam come in and say, You’re part of a big universe; you just don’t know it yet.
Favreau: For me it was just a fun Easter egg for the fans who would sit around until the credits were over. But at that point Kevin was definitely involved in all of that. Because specifically what Sam Jackson says about the Avengers initiative is a way to light that fuse. But for me it was very easy because it was just let’s have him pop in here and there and have him say that. But it was more about getting a reaction from the crowd. Kevin had other plans.