Hereditary, the near-unanimously lauded horror flick of the year, has plenty of in-your-face moments of terror (the film’s spine-chilling ending alone is jam-packed with them). But one particularly unsettling moment — and one that made it into the film’s official trailer ahead of its release — finds its protagonist Peter (Alex Wolff) slamming face first into a classroom desk seemingly against his own control before reeling away in a state of utter horror.

In conversation with the film’s writer-director Ari Aster and Milly Shapiro (who plays Peter’s 13-year-old sister Charlie) following a screening at Brooklyn’s Alamo Drafthouse last week, Wolff spoke to the demanding nature of starring in the scariest films of 2018. In particular, he spoke to the moment his character Peter, while sitting in class, has his head slammed against his desk by an unseen force before reeling back, his face contorted in terror and bloodied from the impact. Turns out it was just as gnarly to shoot as it was to watch.

“I told Ari that I wanted to do it on a real desk. He was like, ‘Dude, we’re gonna get sued. We can’t do that,’” Wolff said, adding that Aster instead suggested a foam desk. “I showed up and it was somewhere in between — it was like foam and really hard at the same time. I could only do [the scene] a few times.”

Speaking with The Wrap, Wolff revealed there was real, honest to god injury and blood involved:

“I had to have the blood shoot out perfectly out of my nose and jump back and do that whole thing,” he told The Wrap. “I remember after, I was just panting, my voice is gone, blood is dripping down everywhere, and blood is gushing down my knee — real blood gushing down my knee because I slammed it against a chair. I couldn’t move my arm, my complete ankle was swollen — it looked like a balloon.”

It would appear there’s more truth behind the horror in this nightmare flick than we’d thought.

Hereditary opened in theaters June 8.

Photos via A24