One of Hereditary’s most astonishing performances was without question that of Milly Shapiro, whose 13-year-old Charlie drives some of the film’s most chilling scenes. In a recent Q&A for the film, Shapiro revealed her method for making her character so freaking creepy.

“Charlie isn’t, to her, creepy, which is something that is interesting to play because she is doing all of these creepy, very strange things,” Shapiro said during a Q&A following a screening of the film at Brooklyn’s Alamo Drafthouse last week. “But to her it’s just normal. So that was very fun for me to do.”

Asked by moderator and Rolling Stone senior editor David Fear about how “draining” the performances were for the film’s stars, Hereditary writer-director Ari Aster prompted Shapiro to describe the method by which she mustered Charlie’s unnerving presence on screen. The young actress revealed that she used the Stella Adler method (a style of imaginative character acting popularized by the actress of the same name) and animal traits — both in physicality and personality — to bring Charlie’s bizarre demeanor to life.

“For Charlie, I chose her outer animal — which is basically the physicality — I chose a turtle because she likes to go inside of herself, and she’s always trying to be hidden,” she said. “And then for her inner animal, I chose a snake because snakes are usually seen as something evil, but they’re also misunderstood. So I thought that would help me with the character.”

Considering her performance has won Shapiro critical praise and helped cement the film as one of the scariest films of 2018, it’s safe to say her method was spot-on. Her incessant clucking certainly helped too.

Hereditary opened in theaters June 8.