It references the Nile, and "the Four Horsemen," the henchmen of the powerful mutant Apocalypse — clearly evoking the post-credits sequence for Singer's film X-Men: Days of Future Past, which became the top-grossing film in the franchise globally.

Singer has long been set as a producer for Apocalypse, but his status on the film as a director has been in flux in the wake of sexual assault lawsuits filed against him in April and May. And BuzzFeed has confirmed that while Singer remains attached to direct the project, he has not yet signed a firm deal with 20th Century Fox for the job.