Next week, Warner Bros. is releasing its latest blockbuster: “Joker: Folie à Deux.” This mainstream Hollywood film is, inexplicably, a comic book adaptation, crime thriller and musical — at the same time.

It’s blindingly apparent that “Joker: Folie à Deux” is aggressively abnormal popcorn fare, and that’s a good thing. In order to understand how it was made, I’m going to talk about something that can be a little scary for Hollywood — politics.

The Overton window was co-created by Joseph Overton and Joseph Lehman at the dawn of the 21st century. It is a political philosophy that states that a specific range of ideas are accepted as reasonable by the general public at any given time. However, this window can shift, bringing formerly unconventional theories to the mainstream.

You may have heard of this idea when discussing the once-shocking rhetoric of former President Donald Trump. But I’d argue that the Overton window should not be limited to political statements. “Joker: Folie à Deux” is the perfect test case for this new philosophy: the Blockbuster Overton Window.

It’s not like director Todd Phillips could have waltzed into Warner Bros. 10 years ago and gotten a movie like this greenlit, especially with its reported $200 million budget. The Blockbuster Overton Window needed to shift in four key ways to make the “Folie à Deux” release possible.

First: “Joker: Folie à Deux” is rated R. It might seem unbelievable now, but there was a time when R-rated movies were not mainstays at the box office. A whopping 17 of the top 20 highest-grossing R-rated movies ever were released in the 21st century.

Phillips’ own filmography contributed significantly to this shift. He directed the “Hangover” trilogy, a set of raunchy comedies which went nuclear at the box office — the first two are still sitting at numbers 10 and 11, respectively, for all R-rated movies.

As the 2010s progressed, movies like “Deadpool” (2016) and “It” (2017) continued to demonstrate that mature movies could succeed in mainstream media. The R-rated “Deadpool & Wolverine” may finish as the second-biggest movie of the year, and its success was exceedingly predictable.

There’s also the issue of characters. “Folie à Deux” is unapologetically about villains — specifically, the titular Joker (Joaquin Phoenix) alongside Harley Quinn (Lady Gaga). Right now, this isn’t a surprising statement, but Hollywood used to be full of films centered squarely on a hero’s journey.

But in the 21st century, the conventional wisdom deeming villains as only supporting characters has received a serious challenge. Disney broke their own fairy-tale mold with the “Maleficent” films. Sony has built a whole universe of villain origin stories. Even “Star Wars” devoted a full third of its mainline saga to the tragedy of Anakin Skywalker.

Just like how villains are a normalized part of blockbuster storytelling nowadays, a darker storyline is also more acceptable than ever. “Avengers: Infinity War” (2018) is a story about an evil purple guy killing and injuring a decade’s worth of beloved characters before exterminating half the universe. It is also one of the highest-grossing movies of all time.

But sure, that’s just a superhero movie. The box office would never respond to a realistically grim story, right? Wrong.

“Oppenheimer” (2023) is a story about the adulterous scientist who built the atomic bomb. The title character is hardly the most sympathetic character in the world, and the movie is rooted in deep emotional darkness, but the film still made nearly $1 billion and won many accolades along the way, including the Academy Award for Best Picture.

The staggering gross of “Oppenheimer” brings us to our fourth and final shift: Blockbusters are allowed to be weirder than they’ve ever been.

In the past 15 months, theaters displayed a three-hour science biopic, a feminist manifesto featuring a personified toy, an erotic tennis drama and a movie adaptation of a musical adaptation of a movie adaptation of a book. But “Oppenheimer,” “Barbie” (2023), “Challengers” and “Mean Girls” all thrived at the box office.

“Folie à Deux” is only the start of a wonderfully weird holiday blockbuster calendar. Upcoming films include a Lego documentary/biopic hybrid starring Pharrell Williams and a “The Lion King” (2019) prequel from “Moonlight” (2016) director Barry Jenkins. Another villain-focused sequel, “Venom: The Last Dance,” will close out October’s blockbuster slate.

The immediate future of blockbusters, especially “Folie à Deux,” make it clear that the Blockbuster Overton Window has shifted. With “Folie à Deux” now projected to make up to $70 million during its opening weekend, these shifts don’t seem to be turning around anytime soon.

Sammy Bovitz is a sophomore writing about the business of film. His column, “Boardrooms & Blockbusters,” runs every other Thursday.