But that’s not enough content for the deepest part of the fan base. If you truly want to live on the bleeding edge of the Marvel-verse, you need to know your rumors.

In the past several years, a sort of industry has grown up around a sprawling network of websites and social media accounts purporting to have the latest scoop, be it that Aubrey Plaza might play the devilish villain Mephisto in an upcoming movie, or vampires might attack Captain America, or a malevolent version of Mr. Fantastic might start destroying worlds.

Very few of these turn out to be true, but the rumors that do pan out can set off chain reactions with dramatic consequences for the Marvel Cinematic Universe that dominates modern Hollywood. So fans pore over every report like Doctor Strange peering into the Time Stone, trying to discern signs of where Marvel’s epic story is headed next.

Some rumor mongers even turn a tidy buck in the process, and have reportedly gone so far as to illicitly fly drones over production lots to glean information. Marvel takes the phenomenon so seriously that it has made a federal case out of leaks.

Last year, a rumor bubbled up on social media that Doctor Doom would appear in a post-credits scene of “Black Panther: Wakanda Forever.” It was one of countless dubiously sourced claims that have emerged from fan-run accounts with names such as @MyTimeToShineHello and @CanWeGetSomeToast. But this one was so loaded with implications that it surged all the way to “Jimmy Kimmel Live!”

See, Doom is a mad scientist who has tormented superheroes for half a century in the comics, but had yet to debut in the Marvel Cinematic Universe, or MCU, the aggrandized term for an interconnected and highly profitable series of movies and TV shows that Marvel Studios launched in 2008 with “Iron Man.”

In the Marvel lore, nearly everything that happens off-page and on-screen takes place in a parallel reality known as Earth-199999. (Or possibly Earth-616; the fan debate around this point would fill the newspaper if we got into it.) So if Doom showed up for even a few frames in “Wakanda Forever,” many fans were convinced, he would inevitably do to the MCU what he had already done to parallel timelines in the comics: invade Black Panther’s country of Wakanda and eventually try to destroy all the superheroes in his timeline. Tom Holland’s Spider-Man, Hugh Jackman’s Wolverine: Half of Hollywood’s A-list might soon be fighting for their lives at a theater near you.

Purported concept art of Doom’s cameo lit up Reddit and Twitter (now X) as theories deepened. At one point, Howard Stern suggested he would voice the character. The influential YouTube channel GeekyCast declared that a “very powerful” version of Doom was “99% confirmed.”

“Is Doctor Doom at the end of the movie?” Kimmel asked “Black Panther” stars Danai Gurira, Lupita Nyong’o and Letitia Wright when they came on the comedian’s late-night show last October. “I’ve heard on very good authority, and maybe this is news to you, too, Doctor Doom will be played by Adam Sandler.”

The Sandler thing was a joke. So was the entire rumor, it turned out. “Wakanda Forever” premiered Oct. 26 with nary a mention of Doom. Fans were let down, but they soon turned to the next unconfirmed report: that Doom might show up in the next Avengers movie.

“It’s just gotten completely carried away in this day and age,” said Jeff Sneider, a freelance reporter who drops Marvel scoops on his podcast, “The Hot Mic,” and for the some 43,000 followers of @TheInSneider, his X account. Among Sneider’s wins is an accurate report that Willem Dafoe’s Green Goblin would appear in “Spider-Man: No Way Home.”

The more substantial rumors can originate from agents, publicists, managers, studio executives or, simply, “people in the know,” Sneider said. Some blogs get their hands on casting grids, too, which are used by agencies to track open roles across Hollywood.

A common source is “a lower-level person in town in their 20s, whose job is to vacuum up information,” Sneider said. “And those are the people that you have to get to know. They’re not the most powerful — although information is power to some extent in this town.”

Of course, many rumors turn out to be invented. Unlike journalistic institutions that Sneider has written for, he said, there’s almost no accountability for rumor sites. Anything a blog throws into the ether is likely to be shared and devoured by fans. If it turns out to be wrong, it’s on to the next one.

“If I was a fan of this stuff, I’d want to go into a movie fresh and just enjoy it,” Sneider said. “But I also understand the flip side. … When there’s demand, there are people who are going to supply that.”

Demand takes the form of people like Brandon Matthews, a Bay Area Marvel fan since age 5 who keeps up with the latest rumors on a daily, sometimes hourly basis.

Matthews used track them all in his head, but he said the volume of rumors drastically multiplied during the pandemic thanks to fans with “endless time on their hands.” Keeping up became a headache. “There will be multiple rumors that release that have contradicting plotlines,” he said.

Matthews now keeps track of the reports on a multi-tab spreadsheet, in which every new rumor is ranked according to reliability on a scale from 10 (a relatively unclear report that Linda Cardellini would appear in “Guardians of the Galaxy Vol. 3,” which actually turned out to be true) to 1 (a rock-solid Deadline story that Will Poulter would play Adam Warlock).

Marvel, which did not respond to multiple requests for comment, has an entire security team dedicated to keeping scripts and plot details from leaking. The meme of Marvel Studios President Kevin Feige with a sniper rifle aiming at leakers exists for a reason.

Marvel stars Holland and Mark Ruffalo have been tight-lipped in recent interviews after they accidentally spoiled plot details in the past. Holland once blurted out on “Jimmy Kimmel Live!” that Spider-Man would be heading to space, and Ruffalo let it slip to “Good Morning America” that everyone dies in “Infinity War.”

Samuel L. Jackson told Entertainment Weekly that Marvel has such high security measures that it has shut down drones trying to fly over production lots. He said someone stole a watermarked version of his script for 2012’s “The Avengers” and set up a fake buy to get it back.

And when the script for “Ant-Man and the Wasp: Quantumania” leaked on a Marvel spoilers Reddit page in January, Marvel went to federal court to try to obtain the leakers’ identities, according to the Wall Street Journal. The legal situation is still unresolved, but the Reddit page was shut down amid the furor, though it has since been resurrected.

Marvel’s rumor industry is the culmination of a phenomenon at least as old as Hollywood.

In the early 20th century, movie magazines would publish columns packed with information on what was happening behind the scenes, said Kendall Phillips, a communications professor at Syracuse University and the host of the “Pop Life” podcast. “And as the studio system grew, the motion picture media journalism grew with it,” he said.

Movie columnists, such as gossip writer Hedda Hopper, often included people working on a film or television show who used to watch daily footage or talk to people on production, Phillips said.

The Washington Post published a section called “Straight From the Studios” in the 1930s, which can seem as breathless and opaque to modern generations as today’s Marvel mill will probably be one day. “Regardless of rumors to the contrary, Paul Lukas will become Philo Vance in ‘The Casino Murder Case,’” read a column in January 1935. “He was chosen when it was determined that William Powell could not undertake the role.”

The industry of leaks transitioned toward “geek culture” around the same time that the MCU ballooned from a niche commodity into today’s juggernaut, according to Joanna Robinson, co-author of “MCU: The Reign of Marvel Studios.”

Because of this, “Marvel has always had like a symbiotic relationship with the geek press,” Robinson said.

Marvel’s rise in Hollywood created an appetite for superhero news, so behind-the-scenes nuggets about the studio’s plans became more common — such as how Emily Blunt was going to debut as Captain Marvel in 2015’s “Avengers: Age of Ultron,” which didn’t end up happening. As Marvel churned out more movies, the blogosphere tossed out more rumors and occasionally managed a true scoop, such as when leaked studio photos from “Avengers: Endgame” showed Captain America in his old costume from 2012, tipping fans off to the movie’s incorporation of time travel.

Casting and plot leaks ballooned around the time HBO’s “Game of Thrones” debuted. That fantasy franchise and the MCU are both based on source material, which makes casting announcements more interesting, Robinson said. People wanted to know whether the undead Lady Stoneheart would appear on “Game of Thrones,” or whether Jon Snow would learn the true identity of his parents.

“It was really interesting to watch that go from somewhat of a niche, relatively Hollywood thing to being a part of the zeitgeist,” said Josh Lucas, who runs the Den of Nerds YouTube channel, which breaks down Marvel and Star Wars news and rumors.

Rumor peddlers The Post talked to didn’t offer specifics about their earnings, but Lucas said he knows YouTube creators who earn six figures from making videos about Marvel leaks and theories.

Speed is key here. The rumor mill moves so quickly that bloggers and webcast hosts are incentivized to jump on any report they come across as soon as possible. Such was the case when “leaks” started circulating that actress Mila Kunis would play Sue Storm in an upcoming film.

Kunis clobbered those theories in an interview with James Corden on “The Late Late Show” in late April. She said she wouldn’t be in the reboot, and the speculation only started because she was seen having a meal with the director.

“Apparently, if you go to lunch with somebody that’s in the industry, you’re going to start working together according to the internet,” she said.

Not long afterward, another rumor popped up claiming that Kunis was going to play a female variant of the Thing. A legion of YouTube videos soon followed. The rumor remains unconfirmed.