Spoiler alert! We're discussing major details about the new horror movie “Cuckoo” (in theaters now).

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In the stylish new thriller “Cuckoo,” “Euphoria” star Hunter Schafer faces off with 2024’s scariest horror creation: a shrieking, Hitchcockian glamazon known as the Hooded Woman (Kalin Morrow). With glowing red eyes and a severe blonde updo, the mysterious monster stalks the rebellious teen Gretchen (Schafer) around an idyllic resort in the German Alps, where hotel owner Herr König (Dan Stevens) is running bizarro genetic experiments on women.

The film is largely left up to audience interpretation, putting a sci-fi spin on familiar themes such as grief, reproduction and the patriarchy. As the movie goes on, Gretchen takes it upon herself to investigate the vicious cloaked figure, whose piercing siren call causes seizures and time loops for anyone in earshot.

“She's being hunted by this strange woman that looks like a disturbed, unhealthy sort of Marilyn Monroe type,” writer/director Tilman Singer says. “There’s something ghostly about her that I cannot put into words, but it's this haunting energy that really gets to me.”

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Here’s how the singular, retro villain came to be:

Kalin Morrow is the blood-curdling breakout star of 'Cuckoo'

Casting the Hooded Woman, Singer knew he wanted a professional dancer. “They can come up with movements that are a little animalistic or robotic or just a bit off,” he says. They’re so in control of their bodies, and can exude “this uncanny, otherworldly feeling.”

Morrow, 38, is an actress and trained ballerina from Oklahoma, who now lives in the Netherlands and teaches dance. To play the character, who has no dialogue, she studied videos of both insects and cuckoos. In movement rehearsals, “we talked a lot about birds: how they might behave when they’re under attack or when they’re waiting for their prey,” she says. “A lot of research went into it.”

The Hooded Woman's glam look is modeled after Audrey Hepburn

Part of what makes the Hooded Woman so eerie is that she’s out of place in the modern world. She’s dressed like an Old Hollywood vixen: wearing a sleek, tan trench coat paired with leather boots, oversized sunglasses and a headscarf. Singer specifically modeled her on Audrey Hepburn, who dons a near-identical outfit in the 1963 thriller “Charade.”

He remembers giving the costume, hair and makeup departments an image of Hepburn in that film. “If you compare them, we went really close to that,” Singer says. “That was my visual inspiration.”

The luminous red eyes, meanwhile, are meant to resemble a cat’s. “We were thinking about how their eyes reflect” light in the dark, Singer adds. “We wanted that glow to shine through her sunglasses.”

Her siren call needed to be 'violent' yet 'musical'

The Hooded Woman’s ear-splitting scream was created, in part, by composer Simon Waskow, who worked with a voice actor to create the distorted yet “ethereal” sound. “We tried a bunch of stuff,” Singer recalls. “It couldn’t be too much of a singing voice, but we also couldn’t go full animal screech. We wanted it to have a certain musical quality.”

“It’s very penetrating,” Morrow says. Although she didn’t contribute her own vocals, “it felt like it was coming out of me. We played a lot with how wide the mouth should be, and how physically, it has to come from the entire body. It felt quite violent, in a great way.”

Hunter Schafer's movie 'Cuckoo' has a shockingly 'emotional' ending

One of the movie’s tensest scenes is of the Hooded Woman sprinting down a dark street and chasing a terrified Gretchen, who is riding a bicycle. “It was a fun day, although I definitely got some shin splints from it,” Morrow recalls with a laugh. “I was in heels, and Tilman was like, ‘Do you want to be in more comfortable shoes?’ I was like, ‘No, she would run differently in heels.’”

The Hooded Woman meets her demise in a bloody standoff with Gretchen, set to the Italian pop song “Il Mio Prossimo Amore” by Loretta Goggi, which translates to “my next love." Her death scene is surprisingly bittersweet: In his twisted medical trials, König has used the Hooded Woman's eggs to impregnate the resort's female inhabitants, in a perverse attempt to create a species with her preternatural abilities.

Gretchen, meanwhile, is mourning the recent loss of her mom and comes to realize that this once-terrifying creature is also a mother with many "children" of her own.

“In a way, that’s what our story is about: to understand where a behavior comes from,” Singer says. “I wanted to make it absolutely clear that she is not a monster. We see her humanity in that moment – there’s something very familiar and familial about her.

"I’m happy to see people connecting to the movie. I wanted it to be a thrill ride, but it can also be very emotional if you’re open to it.”