"Frank is killed in the TU and therefore becomes one of the Manipulated Dead. He travels back in time and helps Donnie with his quest to return the Artifact. The first thing he must do is save Donnie by waking him up before he gets squashed by the jet engine. He is like a reverse ghost who appears before he was killed. Gretchen is also Manipulated Dead but she doesn't appear to Donnie in the same way as it might be to[o] confusing for him."
"Donnie meets the real Frank -- not his Manipulated Dead specter -- for the first time on Halloween eve, with Frank in costume. But it's also an allusion to "Alice's Adventures in Wonderland" -- just as the White Rabbit leads Alice down the hole into her great adventure, so does Frank lead Donnie into his own. Rabbit imagery abounds in "Donnie Darko," from a VW Rabbit driving down the streets of Middlesex to stuffed bunnies to a photograph of toddler Maggie Gyllenhaal next to a kid in a rabbit suit to (in the director's cut) an extended subplot revolving around Richard Adams' rabbits-in-peril novel 'Watership Down.'"
"You all know the face – this demonic, imaginary bunny is now a regular fixture in Halloween celebrations. The costume is based on Frank, the anti-hero from 2001 teen sci-fi drama Donnie Darko. Typically, the skull-faced mask shields the wearer’s face with Frank’s deranged smile and hollow white eyes. ... It’s terrifying, but equally amusing, that a nightmare-inducing mask has become emblematic of such a striking social commentary on American society."