Lee Leshen, who produced the "Back to the Future" documentary "Back in Time," is now turning his attention to "Ghostbusters" and devoted fans with "Ghostheads." But he and the other filmmakers need a little help completing it.

Directed by Brendan Mertens and co-produced by Tommy Avallone, the documentary focuses on hardcore "Ghostbusters" devotees, aka "Ghostheads," who frequently build their own props, from Proton Packs to the Ecto-1, and socialize together, attending conventions, raising money for charities and visiting children's hospitals.

"What makes 'Ghostheads' different them most fandom documentaries is that it’s more than just a love letter film," the producers write, "it focuses and follows different men and women who dress like Ghostbusters and tells their story."

To finish the documentary, the filmmakers have launched an Indiegogo campaign to raise $30,000. Fifteen days into their effort, they're almost halfway to their goal. Pledge rewards range from a listing in the film's end credits and a copy of the DVD to a replica Proton Pack and an executive producer title.