“Why would I do ‘Carrie’ now?”

Samantha Sloyan says this was one of the first things writer, director and showrunner Mike Flanagan said to her when he revealed his idea to turn Stephen King’s 1974 novel of the same name into a miniseries.

Sure, Flanagan had tackled King before, adapting novels such as “Gerald’s Game” and “Doctor Sleep” into acclaimed feature films. But “Carrie” had already been adapted into one of the most famous horror movies of all time, a 1976 masterpiece by Brian De Palma which contained many indelible, nightmarish images.

Additionally, Flanagan was interested in recruiting Sloyan to play Carrie’s religious and antagonistic mother, Margaret White, unforgettably played by Piper Laurie in the film.

But, much like Carrie on prom night, Flanagan wanted to burn it all down.

“He just took everything down to its studs, and then rebuilt the structure,” Sloyan says.

What’s left is a modern tale of school bullying, with a Margaret who is both a zealot and also, thanks to Sloyan, much more human than in the past.

Sloyan is in the enviable position as a loyal member of Flanagan’s stable of actors, and she’s a scene stealer in many of his darkest projects. From their first collaboration in the 2016 movie “Hush” to roles in series like “The Haunting of Hill House” and “The Fall of the House of Usher,” she’s chameleonic in her parts. But perhaps most memorable to horror fans is Sloyan’s lead role as the villainous yet piteous Bev Keane in “Midnight Mass,” in which she weaponized her religious values and became more terrifying than the vampires roaming the seaside town.

Sloyan often hears about these projects in their earliest days, given a personal connection: She’s been best friends with Kate Siegel, Flanagan’s wife and frequent collaborator, since their twenties.

“We’ll be having dinner and cleaning up and he’ll kind of saddle up and just be like, ‘What do you think about Carrie?’ Something like that,” she says. “I’m always like, ‘I don’t … what do you mean?’”

Given her striking work as Bev, it’s easy enough to draw a straight line to Margaret, who in the original text is much more outrageous in her faith. But Sloyan sees two truly different and complicated characters.

“What Mike did with ‘Carrie’ is so much of the horror element: we’re following people along this path and seeing all these times where they could have chosen to behave this way, but instead chose to behave this way,” Sloyan says. “Bev’s on a path for her own glory in a way that’s very single-minded, that’s very selfish, that’s very manipulative. But Margaret is protecting the daughter that she loves. In doing that, Mike sets up all these times as they’re interacting with this world that’s totally new to Carrie and that Margaret has purposefully removed herself from for 15 years. And there’s all these opportunities where she can choose to learn or engage or participate. Instead, she just always chooses violence, to push back, to try to destroy, to undermine, to manipulate.”

Sloyan’s childhood was diametrically opposite to Carrie’s existence, in that she was born to two character actors who encouraged her to become engaged with the world.

“I was born into it, and being raised by character actors, you’re surrounded by really fantastic stories and all different types of people,” she says. “You might recognize them on the screen, but these aren’t people who are walking through life with celebrity having warped everything. But the lifestyle looked so scary because it was so unpredictable and insecure in so many ways.”

Sloyan followed in their footsteps, racking up an impressive roster of recurring roles on hit shows like “Scandal,” “Grey’s Anatomy” and even the first season of “The Pitt” (she plays the grieving mother whose son overdoses on Fentanyl).

But she’s always excited to hear about roles for Flanagan’s projects, because they often push her beyond her own expectations.

“One of the cool things about Bev when Mike said, “I’m hearing you for this,” there was nothing I had done for him that would have indicated that was a character I could do,” she says. “That was really exciting. As an actress, a character like that was thrilling and terrifying. But the second I read her, I understood how she talked, how she moved, what her deal was. With these characters, Margaret and Bev, the connector is obviously Mike Flanagan, who has written people good, bad and complicated. He is writing people we recognize.”

That depth and confidence allowed Sloyan to look past previous depictions of Margaret.

“What I was worried about as an actress was trying to thread was how Margaret was so tangibly dangerous, and that I really wanted Carrie to be stuck,” she says. “You need her to be stuck between these kids in school and her home and not have anywhere to go. So I could love Carrie, but I couldn’t be loving in the way she needed. So I had to make sure that Margaret — and it’s written that way, but also just in my portrayal — could cut Carrie off from her and her love when Carrie wasn’t doing what Margaret needed her to do. That threat of removal of the love.”

Despite that dark undercurrent, stories like “Carrie” are the ones that keep Sloyan energized as an actor.

“I’m still blown away by something that I’ve never seen or been a part of before,” she says. “That’s exciting. There’s a lot to be said for the amount of content that’s being made, but it does mean there are a lot more things to be a part of, that’s for sure.”