At first glance, Midsommar looks like a photo negative of Hereditary, the breakout horror film it follows up. Instead of the grief-stricken Utah home at the heart of Hereditary, director Ari Aster’s new movie takes place in idyllic Sweden, where the midnight sun shines brightly on a twisted summer-solstice celebration happening once every 90 years. Dani, an American college student reeling from family tragedy, is invited by her anthropology student boyfriend to tag along to Midsommar, full of white caftans and psychedelic drugs, as a half-hearted pick-me-up. But as the rituals grow increasingly violent and her friends start to vanish, Dani finds herself at odds with a partner who’s stopped paying any attention to her and a cult perhaps paying too much attention to her. The result is one of the most unpredictable horror movies of the year, and perhaps the most bizarrely cathartic breakup movie ever.

Like Hereditary, Midsommar has some startling twists and a fast-rising body count, but here Aster festoons the corpses with flowers, drenches the gore in light, and adds a welcome dose of gallows humor. While recalling folk-horror classics like The Wicker Man in spirit, Midsommar is very much its own ambitious, 140-minute beast, with a skin-crawling sense of dread anchored by a queasy score from Bobby Krlic, aka the Haxan Cloak. Aster wrote the movie’s script while listening exclusively to the experimental electronic producer, particularly the 13-minute closer off his morbid, throbbing 2013 breakthrough, Excavation. When it came time to add temporary music cues to the film, Aster slotted in even more Haxan Cloak—in his mind, there was no other musician who could score the film. And with Krlic having spent the last few years working on movie music with Atticus and Leopold Ross, he was primed for his own big solo scoring moment.

Sound and music are crucial during Midsommar’s descent into madness, and this required Krlic to incorporate custom-made instruments, sacred chants, and more into his work. He and Aster connected over email in January 2017, before Hereditary was filmed, and then at Krlic’s house in L.A. prior to Midsommar’s filming. “We spent hours rambling on about all the movies we love,” Krlic says. “We would break for lunch and sit at the table and just spend the whole time emphatically talking about film scores and playing records.” We recently hopped on a call with both Aster and Krlic to discuss the ambitious sound of Midsommar.

Pitchfork: What was the process like creating the score for Midsommar?

Bobby Krlic: Ari and I talked to death about what [Midsommar] would be, but describing music with words turns out to be absolutely the most redundant way of doing anything. So Ari came to my house and for about a week we would work from 10 in the morning ’til 7. We tackled the big end scene first, with the idea that it surmises all the emotive qualities that the film’s been building to, expressed in this amazing, nine-minute sequence. So we made that first, with me at the piano and Ari next to me, and he would be so wonderfully descriptive and gestural. I think we were both nervous to start with, and then within a few minutes the whole thing unlocked itself. It was a really great connection that was waiting to happen, that I’d never had doing anything else.

Ari Aster: I had the same experience. This really was one of my favorite collaborations with anybody. I can be very verbose, and what we both found was that it was good for me to talk with my hands. We got to a point pretty early on where you were able to understand exactly what something needed by allowing me to just fuck around with my hands.