Josh Brolin didn’t want to make Weapons.

It’s not because he’s afraid to get his hands dirty. Brolin has spent decades staring into the dark, bringing gravitas to roles in films like Sicario, True Grit and the Avengers franchise that wrestle with fate, masculinity and pain.

Yet as the Oscar-nominated actor steps into the horror genre for the first time in his 40-year career, he says it’s this movie that hits different.

“There’s nothing about me that wanted to do a film like this,” he tells Yahoo about Weapons, in theaters Friday. “Nothing ... other than maybe the selfishness of working with a great director.”

That director is Barbarian breakout Zach Cregger, whose new movie has been kept tightly under wraps since day one. Weapons centers on a chilling mystery: Why did 17 children from the same classroom vanish at exactly 2:17 a.m.? Brolin plays the father of one of the missing kids who, when it becomes clear the authorities aren’t doing enough, takes matters into his own hands.

For Brolin, a real-life father of four, the premise alone was almost too much.

“Things that have to do with kids getting hurt, kids being taken, kids getting lost, being neglected … all that kind of stuff is my absolute living nightmare,” he says, the emotion clear in his voice.

Brolin has two adult children, son Trevor, 37, and 30-year-old daughter Eden, with his first wife, Alice Adair. He wed Kathryn Boyd Brolin in 2016, and they have two young daughters. Being a father is the actor’s favorite role to date.

“I like to think that I give [all of] myself on a very personal level when I work, and then you do something like this, and you realize maybe you haven’t as much as you could," he says. "Because this is so personal to me.”

At first, Brolin wasn’t convinced Weapons was right for him. He passed on the project after reading the script, but then couldn’t stop thinking about it. He’d seen Cregger’s first horror film, 2022’s Barbarian, and had mixed feelings.

“I liked it — but I laughed. So I was confused,” he says. He called his daughter Eden, whom he says is his first call for “everything,” to get a second opinion. She immediately told him Barbarian was one of the best movies of the past five years. “Her husband said the same thing.”

Brolin explains there was something about Cregger's writing he kept coming back to. "There was all this depth where there shouldn’t have been in the horror genre, which is usually very cosmetic and reactive," he says. "And [Cregger] was bringing this new idea.”

That depth is evident in Archer, Brolin’s character in Weapons — a blue-collar worker whose quiet strength begins to unravel after his son disappears. Brolin sees him as a stand-in for the modern everyman: a man weighed down by frustration, resentment and the creeping sense that the world is broken beyond repair. He was drawn to this character, a man who has built layer upon layer of emotional armor, only to realize it can’t protect him from the pain he’s forced to face.

“I like the idea of confronting this masculinity that this guy represents, because I don’t really have a lot of respect for that,” Brolin says. “And I was willing to confront it."

Brolin was excited to play up the tension between who Archer thinks he’s supposed to be and who he is beneath the surface.

"It’s nice to see him kind of break," he says. "I thought it was a good challenge and allowed me to focus on something else other than what happened to the kids.”

Despite some disturbing themes, Brolin threw himself into Weapons, not just as an actor but also as an executive producer.

“Maybe the producer part of me, the older part of me, just wants another great filmmaker in the mix. You’re always hoping for that. And it turns out that it’s absolutely the case — [Cregger's] truly a visionary,” Brolin says.

As someone who’s worked with the likes of the Coen brothers, Denis Villeneuve and Paul Thomas Anderson, Brolin knows the difference between hype and talent. What sets Cregger apart, he says, is his emotional investment. This was evident after a conversation the two had in which the director explained he wrote Weapons from a place of grief, not ambition, following the sudden death of a close friend.

“He’s coming from this really emotional place," Brolin says. "I want to be directed by somebody where it’s that personal. I don’t want to be with somebody where it’s just a job for them."

That propensity for risk-taking and creative freedom is something Brolin values now more than ever, especially after four decades in the business. At 57, he’s far less concerned with box office performance than with telling stories that matter to him in the moment. It's a shift, he tells me, that's happened with age.

“I don’t see all this stuff defining me in any way, shape or form. I’ve seen people that have — Philip Seymour Hoffman comes to mind," he says, referring to the Oscar-winning actor who died in 2014."What a massive impact. And then ultimately, there are young people now who don’t even know who he is." He chooses roles based on what resonates with him at the moment — even if he doesn’t know whether it’ll land with audiences. “I have a feeling,” he says. “An instinct.”

He highlights The Goonies and No Country for Old Men as movies he's done that he believed at the time would have had a lasting impact. "Where people are actually looking back 15 years later and saying, 'That was a pivotal watch for me.'"

He pauses, then says he had the same feeling when he finally saw the final cut of Weapons.

"I didn’t expect what I saw. I knew it was going to be good. … I think it’s very special," he says. "I think it could be one of those movies that people look back on and go, ‘Yeah, I remember seeing Weapons. That was a totally unique take on a genre that had been exhausted.’”

He hopes audiences feel the same way. But for Brolin, the reward was bigger.