Warning: Major SPOILERS for Dark Phoenix.

Dark Phoenix killed Mystique (Jennifer Lawrence) and Jean Grey (Sophie Turner), although eagle-eyed viewers could have predicted that thanks to last year's Deadpool 2Mystique died mid-way through the last X-Men film after Jean accidentally killed her. Jean herself met her end during her final confrontation with the movie's primary antagonist, Vuk (Jessica Chastain).

Marking long-time X-Men film producer Simon Kinberg's directorial debut, Dark Phoenix puts the focus on Jean as she fully transforms into the Dark Phoenix. This is Fox's second attempt at adapting Chris Claremont's iconic comic book arc The Dark Phoenix Saga following the critically-panned X-Men: The Last Stand from 2006. Sadly, critics and audiences alike are less than impressed with the contemporary re-telling, evidenced by its bad reviews and disappointing box office performance.

Related: Why Dark Phoenix's Reviews Are So Negative

Dark Phoenix was marketed as the culmination of almost two-decades of X-Men movies, and that would appear to even include the Deadpool films; Deadpool 2 included a major X-Men Easter egg that established wasn't going to make it out of Dark Phoenix alive.

Deadpool Xmen cross over Deadpool 2

Still grieving over the untimely death of Vanessa (Morena Baccarin), Wade Wilson (Reynolds) moved to the X-Mansion in the hopes of joining the famed superhero team in Deadpool 2. As he roamed around the massive place, he asked Colossus (Stefan Kapičić) why the famous mutants are still nowhere to be seen. This harkens back to Wade's meta-comments in the first Deadpool where he mentioned that the movie's low-budget prevented them from featuring any big-name character from the main saga. As Wade lashed out, the scene cuts around to an open door behind the merc-with-a-mouth, showing the Dark Phoenix-era X-Men in the middle of a meeting.

Notably, Deadpool 2's X-Men cameo only featured Beast (Nicholas Hoult) Quicksilver (Evan Peters), Nightcrawler (Kodi Smit-McPhee), Cyclops (Tye Sheridan), Storm (Alexandra Shipp), and Professor X (James McAvoy). Mystique and Jean Grey were nowhere to be found.

According to Deadpool 2 director David Leitch (via Collider), the X-Men cameo was always in the script, but they weren't sure how to execute it since they primarily shot in Vancouver, Canada while Dark Phoenix was filmed in Montreal. The good thing was, they were shooting at the same time, so the two productions coordinated on how to carry out the scene. Leitch initially worked on the shot, then sent it across the country so Kinberg could frame his part of the scene in a way that seamlessly fit the existing footage.

Related: Dark Phoenix Reshoots Explained: Every Change Fox Made To Their Final X-Men Movie

At the time, Leitch brushed away observations that Jean Grey was missing from Deadpool 2's X-Men cameo by assuming a scheduling conflict, although could easily have been hiding a Dark Phoenix spoiler. Based on the costumes in the scene, though, it's likely Kinberg shot the X-Men moment while filming Dark Phoenix's ending sequence, so neither Turner or Mystique would have been on set anyway.

Whether that's the case or it was intended as sly foreshadowing remains to be seen, but considering Mystique's death was revealed in the trailers and Jean dies at the end of the Dark Phoenix comic, it shouldn't have been too hard for fans to figure out.

More: Dark Phoenix Has A Plot Hole So Big It Breaks X-Men: Apocalypse

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