There's been a lot of buzz and speculation about Fox's X-Men movie universe after the report this week that two of the studio's 2018 films (New Mutants, X-Men: Dark Phoenix) were reshuffled to new 2019 release dates, with major reshoots planned for both. In the case of New Mutants, this was the second major release delay, after the film had already been pushed once.

Naturally, fans have been wondering about what's going on with director Josh Boone's New Mutants adaptation; the first New Mutants trailer generated strong buzz with its superhero/horror blend, and reports are that after the success of IT, Fox wanted to add more horror to New Mutants. However in a new report, we've just learned of a now-defunct post-credits scene in the original version of the film, which would've had massive impact on the larger X-Men movie universe.

According to the Tracking Board, New Mutants would've introduced the character of Mr. Sinister to the X-Men movies, and the villain would've been played by none other than Mad Men star, Jon Hamm! Check out the report below:

"Meanwhile, remember the Essex Corporation that was teased at the end of X-Men: Apocalypse? Well not only was New Mutants going to feature that mysterious company, but The Tracking Board has learned that Jon Hamm was originally going to appear as Mr. Sinister in a tag at the end of New Mutants, and Boone filmed material that led up to that reveal, only for Fox to change their minds after shooting had been completed. Now it’ll be Antonio Banderas playing an unspecified villain (one who isn’t expected to be Mr. Sinister) in the New Mutants tag."

That's a massive change from what Boone and co. originally had planned, to what we're now getting. The Essex Corporation appeared in X-Men: Apocalypse's post-credits scene, when the shadowy corporation obtained a sample of Logan / Wolverine's blood, after his violent escape from the Weapon X program. That blood sample was used to then create the clone Laura / X-23, who we met in Logan's dark near-future. With that connective tissue being strewn together, fans have been waiting for Mr. Sinister to finally emerge as a new big bad in the X-Men movie franchise, and it sounds as though New Mutants would've edged us closer to that happening. And now it won't.

The substitution of Antonio Banderas is a curious one, as we cant help but wonder which X-Men villain the actor could be playing. What are you're best guesses? And how do you feel about Jon Hamm as Mr. Sinister? Let us know in the comments!

Up next from the X-franchise is Deadpool 2, out May 18. X-Men: Dark Phoenix opens February 14, 2019, followed by The New Mutants on August 2, 2019.