The Russo Brothers have once again sparked fan excitement with a new teaser for Avengers: Doomsday. Via InstagramThe black-and-white image shared by the Russo Brothers features a tent, scaffolding, and lights that fans believe form the outline of Doctor Doom’s mask. This makes sense, as Robert Downey Jr. is set to portray Doctor Doom, who will be the main villain in the movie. Both theories tie back to existing Marvel lore: Doctor Doom was referenced in The Fantastic Four: First Steps and appeared in a post-credit scene, while Avengers vs. X-Men has long been a popular comic theme. The story takes place fourteen months after the events of Thunderbolts* and follows the Avengers, Wakandans, Fantastic Four, New Avengers, and the original X-Men as they team up to face Doctor Doom.