The Story Behind 'Happy Death Day''s Creepy Baby Mask and Tree's Best Lines

The baby mask worn by the killer in Blumhouse Productions' "Happy Death Day." Universal Studios

Horror director Christopher B. Landon (Paranormal Activity II, III, IV and V) may have a monster hit on his hands with Happy Death Day, his newest film with Blumhouse Productions. No film company has the box office by the throat quite as well as Blumhouse, which pumps out low-budget scary movies to critical acclaim and box office success month after month.

The film's conceit is simple: a killer in a baby mask murders a sorority "mean girl," but instead of dying, Theresa "Tree" Gelbman (Jessica Rothe) wakes up at the beginning of the day she died. Tree quickly realizes she's stuck in a time loop until she can figure out who her killer is. In other words, her #blessed sorority life just, like, totally sucks now.

Jessica Routhe as Tree in "Happy Death Day." Universal Studios

Landon tells Newsweek that his Groundhog Day slasher homage is supposed to make you laugh as often as you jump in your seat. "Every movie I've ever made has combined horror with comedy," he says, "because I believe that jokes and scares have the same basic construction. You disarm them with a laugh, ramp it back up with a scare, and shock them. It's great if you can do it all at once," Landon says.

RELATED: The best horror movies of 2017, ranked

What could have been a cheesy, B-movie thriller benefits enormously from the compusively likable Rothe, who adds her iconic scream face to a decades-long list of women in horror. As Tree, she banters with other sorority girls, lets out a 30-second fart after a joke for emphasis, and bends her facial expressions with an elasticity reminiscent of a young Jim Carrey. "She's a movie star," Landon says, "and she was my partner in crime through this whole thing." Early in the film, while trying to reject a stalker-esque date, Rothe deadpans, "Who takes their first date to Subway? It's not like you have a foot-long." That punchline, Landon says, was Rothe's off the cuff improvisation.

But it's not just Happy Death Day's leading lady that makes the horror film unique. The killer's baby mask, with its wide eyes and single tooth, is a difficult image to forget. Landon explains it was constructed by Tony Gardner, the same man who built the infamous "Ghostface" mask from every Scream film, and that its design was personal. "During preproduction," Landon explains, "I was expecting my first son. I don't know if I just had babies on the brain, or if I was subsconciously scared to become a father, but that baby image was floating around in my head. Tony made us a pig mask, too, but when I wore the baby mask in the office, I scared a co-worker, and we thought...yeah, this is it. This is the one."

The baby-masked killer in "Happy Death Day." Universal Studios

That baby mask follows Tree across campus, killing her in myraid ways—stabbing her, breaking her neck, lighting her car on fire—until she wakes up to the sound of her irritating ringtone. Though the film's trailer used 50 Cent's "In Da Club" as her ringtone—"go shawty / it's your birthday / we gonna party like it's your birthday"—Landon says the film couldn't afford to use the recognizable track. "Our music supervisor Andrea improvised, and I actually like what she came up with a lot better. Tree clearly didn't pick the ringtone for herself, it's so annoying." Fans of the film will undoubtedly search for it online, though it's not currently available.

Happy Death Day, which is already projected to unseat Blade Runner 2049 as the top film at the box office, opens nationwide Friday. Produced for just $5 million, it is expected to gross $20 million its opening weekend, adding yet another successful horror film to 2017's impressive list of scares.