You just don't get as many wild theories based on IMDb listings as you used to, and for good reason: the website is editable by far more people than just the movie studios themselves, and it's not at all uncommon for incorrect or incomplete information to show up there. At one point, for instance, there was a well-publicized rumor that held Cobie Smulders was going to be playing a Skrull princess in Marvel's The Avengers. But there's a new one floating around that's pretty interesting, and seems to have at least a little more circumstantial evidence to back it up.
The rumor? Harry Lennix will appear in The Flash in the role of Martian Manhunter. The IMDb connection? This notion came to fans' attention when a stunt performer was listed as working for the film as Lennix's double.
The stunt performer, Kenny Knight, has previously appeared in Wrath of Man and Cruella, and is set to appear in Marvel's Eternals. After fans on social media started to take note of the listing (screenshotted for posterity by The Cosmic Circus), the listing on IMDb was modified, so that Knight's name remains attached to the film but any connection to Lennix has been removed. That said, the actor did recently follow Lennix on Instagram, which could indicate that the pair have recently met.
There are a few mitigating factors here, so let's unpack those.
Lennix first appeared in Man of Steel, playing General Calvin Swanwick, a U.S. military official who crossed paths with Superman a few times. The revelation that he could be Martian Manhunter is something that fans and Snyder started buzzing about quietly around the time of Batman v Superman: Dawn of Justice, and it didn't pay off completely until Zack Snyder's Justice League was released on HBO Max.
Lennix is a hire closely associated with Zack Snyder and, while it doesn't thrill a lot of fans, the studio seems to be moving away from Snyder's vision for the DC films. That doesn't feel like enough of a reason to abandon a major character, but remember that Swanwick and Martian Manhunter have not had a ton of screen time. He's only a "major" character because fans know how important Martian Manhunter is outside of the context of the movies.
Lennix also might return...but play General Swanwick. The Martian Manhunter reveal happened exclusively in Zack Snyder's Justice League, and at this point, it does not seem that elements of the Snyder Cut that didn't appear in the 2017 theatrical version will be considered canon to the wider universe.
It's also difficult to know which came first: Knight following Swanwick on social media, or being listed as Swanwick's stunt double. If the listing happened first, whether it's accurate or not, the momentum it picked up on social media could have made Knight more interested in Lennix's work, and pushed him to follow the actor in the time between the birth of the rumor and when The Cosmic Circus decided to do some sleuthing.1comments
So, all in all, it's certainly worth bringing up the question, especially in a movie as shrouded in mystery and full of "guest" superheroes as The Flash. Barring any kind of official confirmation, though, an IMDb listing and a social media follow is hardly a smoking gun. It's likely fans will have to wait until the movie is actually out to see for themselves.
The Flash features Ezra Miller, Kiersey Clemons, and Ben Affleck, reprising their roles from Zack Snyder's Justice League. Michael Keaton's Batman also returns, alongside fellow DC Films newcomer Sasha Calle, who will play Supergirl. The Flash is currently scheduled to open in theaters on November 4, 2022.