20th Century Fox and director Bryan Singer are still keeping details on 'X-Men: Apocalypse,' the recently announced sequel to 'Days of Future Past,' under wraps, but potential details have been leaking out. The biggest question on many fans' minds is, how will the sequel build off of 'Days of Future Past'? As of now, it looks like that will happen via the post-credits scene, which has been revealed in its entirety.

[SPOILER WARNING: Stop reading now if you want 'X-Men: Days of Future Past' to be kept a surprise.]

Inside sources mapped out the full extent of the 'X-Men: Days of Future Past' post-credits scene to First Showing, and it seems as though it's a teaser for 'X-Men: Apocalypse,' though fans of the iconic comic-book villain (and Magneto, for that matter) might be disappointed in his presentation ...

Here's the short version: Following the events of 'Days of Future Past,' the Magneto of the past (Michael Fassbender) is on the run from authorities when he encounters Apocalypse, who descends from the sky. The mutant -- described as "towering, terrifying, with a twisted metal face and dark pits for eyes" -- reveals he's traveled through time to find Magneto, who he then possesses. (For a more detailed rundown of the scene, click over to First Showing.)

While the just-described scene doesn't necessarily mean that this is how Apocalypse and Magneto will be rendered throughout the entirely of the forthcoming 'X-Men: Apocalypse,' it does seem like a disservice to the villain. One of Apocalypse's many abilities is transferring his consciousness and abilities to other bodies, but fans of the franchise are expecting to see this baddie fully rendered onscreen and not just locked away inside Magneto's body. Furthermore, what does this mean for the original cast's involvement? Will there be another alternate timeline in which folks like Ian McKellen, Patrick Stewart and Halle Berry are involved in some way?

[UPDATE: Bryan Singer denounced this report to Empire magazine, saying, "That's not the case ... and neither will that particular thing be in the film. People were concerned we were making Apocalypse an alien. It's odd. I don't know where that came from."]

There's still plenty of time left until we see 'X-Men: Days of Future Past,' starting May 23, 2014, but we'll keep you up to date on this front. 'X-Men: Apocalypse' will follow on May 27, 2016.