10 Best MCU Deleted Scenes EVER
3. "Radioactive Bug Bites And Assorted Mutants" - Iron Man
The closing credits of 2008's Iron Man famously had Nick Fury conversing with Tony Stark. There, Samuel L. Jackson's Fury makes mention of the Avengers Initiative to RDJ's Stark.
In an earlier cut of this scene - a cut that obviously didn't make it into the movie - part of Fury's berating of Iron Man sees him mention "gamma accidents, radioactive bug bites and assorted mutants".
While the use of gamma accidents was a clear indicator of the next film in the burgeoning MCU - that being The Incredible Hulk - the radioactive bug bites and assorted mutants terms are nods to Spider-Man and the X-Men, respectively.
At this point in time, Sony Pictures had the exclusive rights to anything cinematically related to Spidey, whilst the movie rights for Professor X and his merry band of mutants were housed over at 20th Century Fox. As such, any mention of these characters in Iron Man or the MCU back then would have been references to characters that were out of reach.
Since then, Sony and Disney have come to a working agreement where Spider-Man can be involved in the MCU. As for the X-Men, they're now fully under the House of Mouse banner after Disney outright bought 21st Century Fox - and subsequently properties such as X-Men, Alien, and Avatar - in March 2019.