The 24th Boston Underground Festival returns Wednesday to celebrate horror in its many guises.

Opening night: The East Coast premiere of “Immaculate” with Sydney Sweeney (“Euphoria,” “White Lotus 1”).

“It’s a dark, fun film with some thought behind it, very much in the realm of ‘Black Narcissus,’ the Michael Powell film,” explained festival programmer Nicole McControversy of the 1947 classic about nuns going mad in the Himalayas.

“We get to see Sydney explore her range as a performer as a young novitiate about to become a nun who goes to this idyllic place in Italy. She thinks she’s found her sisters and God. But dark stuff is at play.”

For McControversy, at BUFF since 2008, each festival takes, “A look at what’s going on in the world of horror. Usually it’s dystopian anxieties, communal strife.”

“Boy Kills World,” another East Coast premiere, stars Bill Skarsgård (“It,” “John Wick: Chapter Four”) as a deaf man with a mission. “That is one very wild out-there action movie. We get to see Bill and his fighting chops. The choreography is brilliant!

“It’s got a ‘Kill Bill’ framework, a vengeance story.  He’s training in forests with a shaman and the film follows his journey.”

From Canada comes the slasher film “In a Violent Nature,” one of McControversy’s favorites. “That film in particular takes a familiar format, a slasher film you’ve seen from the ‘80s, and does something very different. It puts us in the perspective of the slasher. There’s a lot of moments where you’re standing in his body in the woods watching teenage shenanigans play out. And then,” she laughed, “he goes and kills them.  It really pulls apart the things that make a slasher film.”

BUFF’s film slate, said Kevin Monahan, its artistic director since 2005, isn’t meant to be so underground it’s a fringe event.

“When I first started doing this, I wanted to put a hand grenade in people’s faces,” he said of equating shock with artistic integrity. “But I’ve matured a lot. While we always feel the need to provoke, we don’t go after it. It happens organically because of the films.

“One film I’d like to direct people to is ‘Strange Kindness,’ which rates as a world premiere Thursday. It’s a quiet, low burn character-driven piece that was shot in Cape Cod. So the filmmakers are local as is the talent — and we’d love the community to come out specifically for this.”

Currently the only way to see “Strange Kindness” is at BUFF — they have no distributor yet.

“The hope,” said McControversy, “is the industry will take notice. The dream is that it would be picked up.”

The 24th Boston Underground Film Festival runs at the Brattle from March 20 – 24. Individual tickets are $15, a BUFF badge for every entry is $150.