The behind-the-scenes story of Donnie Darko's creepy bunny suit

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Even Donnie Darko writer-director Richard Kelly isn't quite sure how to answer when asked how he came up with the eerie bunny suit for his hallucinatory character, Frank. "Everyone asks me, 'Where did the rabbit come from?'" he says with a laugh. "And it's not an easy question to answer."

It's been more than 15 years since Kelly introduced us to the morose Donnie Darko (Jake Gyllenhaal) and his world of airplane engines and Sparkle Motion. The now-cult classic includes characters played by everyone from Maggie Gyllenhaal and Jena Malone to Patrick Swayze and Seth Rogen, but there's one face that stands out, even in this eclectic cast of misfits. James Duval plays Frank, an enormous imaginary rabbit who informs Donnie that the world is going to end in 28 days.

Even in the earliest drafts of the script, Frank was always a rabbit. The design may have come to him in a dream, Kelly says, or maybe subconsciously from his longtime love of Watership Down. (In fact, there's a scene in the director's cut of the film where Drew Barrymore shows the film version of Watership Down in her classroom.) One thing that wasn't an influence was the other film about a six-foot rabbit. "I've still never seen Harvey," Kelly admits with a laugh.

The director sketched out Frank's face himself before the cameras started rolling—some of his initial drawings can be seen in the film's final "Mad World" montage—and costume designer April Ferry (Game of Thrones) brought Frank to life, building the fur suit herself and recruiting a sculptor to create the twisted grin. Because Frank doesn't have to perform any big stunts or even do much walking in the film, the mask itself has extremely limited visibility. "I was very adamant that it had to make an impact," Kelly says. "It has to disturb people. It has to make the audience sit up in their seat and have a really intense response."

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The first test of that response came early, when the cast and crew got their first glimpse of Frank only a few days into shooting. Kelly was only 24 years old at the time, having never directed a feature film before, and he felt himself still trying to earn his crew's confidence. "When we brought the rabbit on set, that was a moment where I knew I was either going to live or die by the rabbit and how people responded to it," Kelly says. Duval wore the Frank suit in almost every single scene on the movie, but on that day, a producer stepped in—and when Frank walked on set, Kelly could feel the mood change.

"Everyone just got quiet on the set," he recalls. "Everyone was like, this is really intense. So I knew it was working, and I felt the sense of relief. I could look around, and the makeup artist and the production assistants and the second AD, they were all just really freaked out about it. Steven Poster, my cinematographer, came up to me, and he was like, 'Rich, I wasn't sure about the rabbit… but now I get it.'"

Audiences reacted in the same way. Donnie Darko was a box office flop when it first hit theaters in October 2001—a film about a jet engine falling from the sky didn't seem particularly palatable in the wake of Sept. 11—but in the years since, the bizarre tale has become an undisputed cult classic. Above all, it's images of the rabbit that remain popular, spawning countless Halloween costumes and T-shirt designs. Recently, Kelly got a Twitter direct message from actress/model Paris Jackson (daughter of Michael), who sent him a picture of the Frank tattoo on her forearm.

As for Frank's current whereabouts? Beauty and the Beast co-producer Jack Morrissey collects movie memorabilia, and he currently owns the main mask and suit (photographed by EW above). A second backup mask belongs to Metallica's Kirk Hammett, who's apparently a fan of hair-raising hares.

"There's tattoos, there's artwork, there's sculpture, there's merchandise, there's people who do paintings," Kelly says. "It just continues to be a story and a film that resonates with people."

Starting Friday, a special 15th anniversary, 4K restoration of Donnie Darko will begin playing in select theaters around the country. For screening and location info, head here.