Body horror is typically associated with David Cronenberg and other modern directors, but the Brothers Grimm may have invented the genre back in the 1800s.

Their version of the Cinderella story, a folktale that had been told, adapted and retold since the turn of the last millennium, had the ugly stepsisters mutilating their own feet so that the slipper left behind by Cinderella at the ball would fit their feet, presumably less tiny than their rival. Spoiler: It didn’t work.

The Ugly Stepsister, coming to theaters next month, the transformation is a little more involved, and apparently a lot more gory. Written and directed by Emilie Blichfeldt, the film follows Elvira (Lea Myren), a young girl who finds herself brought into her father’s new family, yet more alone than ever.

Elvira’s competition for the hand of the prince is Agnes (Thea Sofie Loch Næss), who is effortlessly beautiful, as well as more cultured, poised, and connected than her unfortunate step-sis.

Naturally, there’s a ball to attend and a prince to charm, so Agnes and her mother concoct a way to help their new relation. Elvira prepares to earn his affection at any cost, including extreme surgery in an era before anesthetic was commonly used.

Ane Dahl Torp, Flo Fagerli, Isac Calmroth and Malte Gårdinger also star.

The Ugly Stepsister premiered at the Sundance Film Festival, where it generated plenty of buzz and caused at least one audience member to lose their lunch during a screening. The film’s original title is Den Stygge Stesøsteren, and hails from Norway, just across the sea from Germany, the home of the Brothers Grimm.

The Ugly Stepsister makes her debut in theaters on April 18th.