Qualley tells PEOPLE how the body-horror film, directed by Coralie Fargeat, pushed her to take risks onscreen Embodying her character in The Substance challenged Margaret Qualley to take new risks onscreen.

Due to time constraints, Persin subcontracted the build of Monstro Eliasue’s suit to a U.K.-based company. “We had two full suits, one for a stunt double, and a half-built suit for Margaret, which she wore for closeups.” Persin and his team took care of all the effects, including the boob that squeezes out of one of Monstro’s many holes.

Despite the film's darker themes and gory visuals, Moore and Qualley created an environment where they could find comfort and be their best.

Demi Moore tells PEOPLE she hadn't met Margaret Qualley before becoming her costar in Coralie Fargeat’s new horror movie 'The Substance,' but had enough 'indirect connections' that they 'felt like we

Full of bold colors, detailed close-ups, and tearing flesh, “The Substance,” directed by Coralie Fargeat, takes body horror to a new level. The commentary on Hollywood’s treatment of women and the concept of “aging gracefully” can’t go unnoticed.

Obviously, between all of the scenes of spine-splitting, vomiting, close-up injections and Dennis Quaid chowing down on a plate full of prawns, the whole film wasn’t exactly a walk in the park, but there was really no preparing for the birth of Monstro Elisasue in the final act, was there?

From daunting high-energy choreography to nine-hour prosthetic application, the stars tell EW "The Substance" was a satisfyingly grueling, months-long shoot.

She and costar Margaret Qualley also devoted time to perfecting sexualized gyrations their celebrity fitness characters would perform in front of leering cameras and a slimeball of a boss, played by Dennis Quaid,