Marvel Studios boss Kevin Feige surprised San Diego Comic Con attendees with exclusive footage from “Avengers: Doomsday,” shown only to lucky fans inside the convention center’s massive Hall H.

The trailer begins with Victor Von Doom (Robert Downey Jr.) sitting on a throne while Vanessa Kirby’s Sue Storm (aka the Invisible Woman) explains how he is broken as a person. “Victor was always the smartest guy in the room. He used to be different,” he narrates darkly. It’s clear that she and the rest of the Fantastic Four, particularly Pedro Pascal’s Reed Richards, already know Doom and have a complicated past with him. “Everything he loved was taken away from him,” he explains.

The trailer is interspersed with quick shots of the extensive cast, including Thor (Chris Hemsworth), Captain America (Chris Evans), Black Panther (Letitia Wright), Shang-Chi (Simu Liu), Loki (Tom Hiddleston), Cyclops (James Marsden), Magneto (Ian McKellen), Gambit (Channing Tatum), and more. There’s a shot of a New York City destroyed and reduced to rubble, and Pedro Pascal’s Reed Richards asks if Victor is responsible for the carnage.

We hear Doom say, “You have all lived stolen lives.” Thor confronts Doom, but the villain catches his magic hammer and easily tosses it aside. Doom uses his magical powers to push Thor aside and raises an army of Sentinel robots (the iconic androids from the “X-Men” movies) from the ground.

MCU fans will have to wait until December 18 to see “Avengers: Doomsday” for themselves, but it’s expected to be a big team-up between the Avengers, Fantastic Four, Thunderbolts, and even more Marvel stars.

The countdown to “Doomsday” began last December when Marvel released four trailers to start getting fans excited for the flagship film. They featured the return of Chris Evans as Captain America, who now has a son, Chris Hemsworth’s Thor and his daughter Love, the Fantastic Four meeting Black Panther and the Wakandans, and the official MCU debut of Fox’s former X-Men team.

The “Doomsday” cast is led by Downey Jr. as the villain Doctor Doom, plus “Avengers” stars such as Evans, Hemsworth, Paul Rudd, Sebastian Stan, Anthony Mackie and Simu Liu. The “Fantastic Four” and “Thunderbolts” teams, consisting of Pascal, Kirby, Joseph Quinn, Ebon Moss-Bachrach, Florence Pugh, David Harbour, Wyatt Russell, Hannah John-Kamen and Lewis Pullman, will also join the original stars.

Cast members from Fox’s “X-Men” will also be moving over to the MCU for “Doomsday.” Returning stars include Patrick Stewart, Ian McKellen, James Marsden, Kelsey Grammer, Alan Cumming, Rebecca Romijn and Channing Tatum.

Check out a new poster for “Avengers: Doomsday” below.