We still have quite some time before ‘X-Men: Apocalypse’ is unleashed in theaters, and while the film doesn’t even begin shooting until April, Bryan Singer is already teasing fans with the promise of new and exciting things—like a photo of something old that’s ready to be made into something new again. That something? Well, it might be Cerebro. And it might be something else.

The director took to his Instagram to post a photo from the set of ‘X-Men: Apocalypse,’ and while it doesn’t show much, it does feature a door that will look very familiar to fans—it appears to be the X-emblazoned door leading to Cerebro, Professor Xavier’s psychic device that allows him to find any mutant, anywhere on Earth.

But it might not be Cerebro’s door. Singer’s caption on the photo indicates that this door will lead to something we haven’t seen before. And it doesn’t seem too likely that he would have reinvented the insides of Cerebro. Some fans are speculating that this could be the door to the Danger Room, the training facility we first saw in ‘X-Men: The Last Stand.’ Singer originally placed the Danger Room facility in the first ‘X-Men’ film, but had to cut the sequence from the movie. He tried to integrate the Danger Room in ‘X2,’ but was unable to use it due to his budget.

Perhaps Singer still has the itch to include the facility in an ‘X-Men’ movie? We’ll know soon enough. ‘X-Men: Apocalypse’ hits theaters on May 27, 2016.