Marvel's Avengers: Doomsday X-Men Trailer Confirms The Debut Of Major Villains

Given the huge, huge cast for "Avengers: Doomsday," the movie's marketing campaign has opted to do something a little different for its opening teaser. Rather than a single one, there are multiple "Doomsday" teasers rolling out to let casual Marvel fans know old favorites are returning: Chris Evans as Captain America, Chris Hemsworth as Thor, and, as the newly-released third "Doomsday" teaser highlights, several "X-Men" characters from the 2000s 20th Century Fox X-movies.

The money shot of the "X-Men" teaser is undeniably Cyclops (James Marsden), dressed in a blue-and-yellow costume right out of the 1990s "X-Men" cartoon, kneeling down as he lets loose an enormous optic blast. Behind Cyclops, though, are some enormous metallic boots: "X-Men" fans will recognize those as Sentinels, the skyscraper-sized mutant killing robots and some of the X-Men's go-to enemies since their 1965 debut in Stan Lee and Jack Kirby's "X-Men" #14.

The 2000s "X-Men" films went for a stripped down aesthetic and storytelling that eschewed (some might even say dulled) the colorfulness of the comics. That meant no Sentinels in the original trilogy; the closest thing it had was a single Sentinel (well, its decapitated head) in a Danger Room simulation. The Sentinels finally debuted properly onscreen in 2014's "X-Men: Days of Future Past," adapting the comic storyline all about a dark future where the Sentinels have almost exterminated mutants.

The "Days of Future Past" movie sized down the Sentinels, making them only about 10-feet tall rather than several stories high. Based on the scale of the "Doomsday" teaser, though, these Sentinels look like they'll be as big as the comic book ones.

Sentinels are a convenient villain for the X-Men. They're robots, so that means they can be destroyed as violently as possible without any censorship concerns. In "X-Men" cartoons, Wolverine can't slice up flesh-and-blood villains with his adamantium claws, but he can do that to Sentinels. Created by humans who fear and hate mutants, Sentinels are intrinsically tied to the "X-Men" franchise's themes about prejudice and evolution. Like our ancient ancestors were against predators, non-mutant humans are outmatched physically against mutants, so we create technology to level the playing field. The problem is, the Sentinels rarely stay under control.

"Days of Future Past" depicted a variant of Sentinels that could absorb and duplicate mutant powers; whenever these Sentinels fought the X-Men, it wasn't a battle so much as a slaughter. Could we be looking at another mutant massacre? Cyclops' actions in the teaser suggest despair. "Doomsday" is being followed by "Avengers: Secret Wars," and that storyline suggests the multiverse will collapse; perhaps the X-Men's world is doomed, so new variants can be added to the Marvel Cinematic Universe's "sacred timeline" for future movies? Moreover, Doctor Doom (Robert Downey Jr.) — the villain of "Avengers: Doomsday" — is a genius with robotics; he has an army of "Doombots" at his beck-and-call. Perhaps these Sentinels are, in fact, merely plus-sized Doombots?

"Avengers: Doomsday" hits theaters on December 18, 2026.