It wasn’t clear if Marvel Studios’ grand experiment was going to work out until The Avengers became a huge hit in 2012, but anyone could tell before the movie came out that the studio was working toward something special. So special, apparently, that Fox was already getting jealous. According to X-Men: First Class writer Zack Stentz, he had been working with 20th Century Fox in 2011 to develop a “secret movie” that would’ve featured every Marvel superhero the studio had access to at the time—meaning the full casts of The X-Men (including Deadpool) and The Fantastic Four, plus Daredevil.
Stentz revealed this on Kevin Smith’s Fatman Beyond podcast (via /Film), and while he couldn’t give away specific plot details, he said he was “really proud” of the script and that Fox almost convinced Paul Greengrass to direct. But what could the plot have been? Well, most of Marvel’s most famous comic events do prominently feature The Avengers (they get slaughtered in The Infinity Gauntlet, but they are are there), but with The Fantastic Four rights in play, Fox would’ve had access to an even bigger bad guy than Thanos: Galactus, The Devourer Of Worlds, who still has yet to make a proper movie appearance after Fantastic Four: Rise Of The Silver Surfer depicted him as a mean space-cloud.
Stentz didn’t say Galactus, but there aren’t really any other obvious directions for a story featuring The X-Men, Daredevil, and The Fantastic Four to go in—unless Fox beat Marvel to Civil War and did, like, Fantastic Four Vs. X-Men And Also Daredevil. Of course, while this does present an interesting “What If?” scenario, there’s a reason it didn’t happen. The Avengers proved that there’s a huge market for good stories about comic book characters that build toward something bigger, but not only has no other studio managed to pull off something similarly successful, but Fox itself had an extremely spotty record when it came to its Marvel movies. The studio never managed to get The Fantastic Four right, so it seems extremely unlikely that it could’ve gotten The Fantastic Four and The X-Men and a pre-Deadpool version of Deadpool to work in the years before Marvel Studios proved that it can be worthwhile to throw a ton of money at comic book movies.