Following the London premier, a post-credit teaser scene from X-Men: Days of Future Past was added to the film The Amazing Spider-Man 2, due to an existing deal between Webb and 20th Century Fox. To give some context, Marc Webb was supposed to make another film for Fox Searchlight after ‘500 Days of Summer’. Fox, however, allowed him to direct ‘Spider-Man 2′ just as long as Sony included a free preview for ‘Days of Future Past.’
The scene’s inclusion sparked confusion among some fans, who incorrectly thought an X-Men / Spider-Man crossover film was being planned, based on how Marvel Studios and Disney use end credit scenes within the MCU (Marvel Cinematic Universe) to promote future films.
The scene itself is set during the Vietnam War, and sees Mystique breaking into a military base on her own, to liberate several mutant soldiers who have been detained and are set to be shipped to a “private facility”; among these mutants are Havok and Toad. We are also given a look at the younger version of William Stryker, who appears to be in charge of the operation to subdue them and bring them to the facility.
The scene has been released online, and May 23rd cannot come quickly enough!