The following article contains spoilers.

With united cinematic universes en vogue for blockbuster superhero movies, 20th Century Fox couldn’t pass up an opportunity to include Marvel’s wise-ass assassin, Deadpool, as a part of their long-running X-Men movie series. But X-Men wields a confusing and convoluted continuity, and Deadpool has no mention or cameo of any established X-Men (we’ll get to Colossus in a bit). So what’s the deal with Deadpool and X-Men?

First, you should know that nothing matters before X-Men: Days of Future Past. The ending to the 2014 X-Men movie was a big reset of the entire continuity; Wolverine’s adventure to the ’70s altered timelines, changed fates, and redefined everyone’s relationships. Cyclops and Jean Grey, who died in X-Men III: The Last Stand, are now alive and well. The current timeline that the X-Men live in is vastly different from what was started in the first X-Men from 2000.

That means Deadpool slips right in to the current continuity without hassle. So the Wade Wilson in X-Men Origins: Wolverine, the maligned 2009 prequel, isn’t the same Wade Wilson you see in Deadpool. Wolverine’s alteration of the timelines allowed Wade to live a different life but still end up a subject for advanced weapons testing. And it isn’t the Weapon X program, the same one that created him and Wolverine in X-Men Origins.

This distinction, of course, is made implicitly, because actually mentioning or including this complicated nonsense would put off so many of the audience who just want to see Ryan Reynolds kill dudes.

As far as Deadpool’s involvement with the actual X-Men themselves, Colossus — who bizarrely represents a more traditional superhero id than he ever has in comics or film — has kept an eye on Wade. He wants to recruit him and straighten him out at Xavier’s school, which Deadpool visits briefly, complete with mention of Professor X by name. (No cameo.)

In Deadpool, Colossus is different, noticeably bigger, and more talkative than the previous X-Men continuities showed him.

Colossus, however, still presents continuity problems. He lives through Wolverine’s reset and is seen as his old self at the end of Days of Future Past. He stands next to Kitty Pryde during a lecture, implying both a professional and personal relationship between them.

Now in Deadpool, he’s a new man and it’s not addressed or explained, cementing it as a very glaring wrinkle in the continuity. This wouldn’t happen in the main Marvel Cinematic Universe, and your mileage varies as to whether or not that’s a good thing.

And no, besides Negasonic Teenage Warhead and Angel Dust or anybody obvious, no other X-Men or mutants are seen throughout Deadpoolincluding Wolverine. But relax, this stuff makes up some of the movie’s best jokes. And, honestly, that’s all that matters about Deadpool.

Then again …

The initial press screenings some of us at Inverse attended saw a fun but unimportant post-credits scene. According to Alan Cerny of Ain’t It Cool News, there’s another post-credits stinger for the theatrical release, not yet seen by the press.

It’s a claim backed up by the very creator of Deadpool, Rob Liefeld.

In a November 2015 interview with Collider.com, Deadpool screenwriters Rhett Rheese and Paul Wernick discussed a post-credits stinger that sounds way bigger and more involved than a fun Ferris Bueller homage. (Hey, I did say spoilers.)

Wernick: There is a post-credit thing that, if hopefully comes together, it’s gonna be phenomenal.

Reese: We’re planning it. It’s one of those ones that’s gonna require some doing, so it may not come together, and if so, I don’t know, we’ll either do a plan B or none at all. I think we should have one, I mean, we really feel like we should have one.

In that same interview, Reese was quoted at length about Deadpool and its place in the X-Men timeline:

“And we are part of the X universe, and that is important. Simon Kinberg is our producer and he kind of minds the store in regards to the X universe, so we are fitting into the larger timeline … Deadpool is very much of that world and I think sooner or later we’ll cross over into that world. I mean, we’re not sure when that would be. Probably, if I’d have to guess, we would do a standalone sequel before he entered the actual ensemble movies, but I think at some point it will cross over and it needs to fit.”

With X-Men: Apocalypse coming this May, maybe we can expect to see Wade aboard a Blackbird, or Wolverine cuss out Deadpool after all.