The Hell's Satans cruise the streets of Richmond.

To make Satan Since 2003, a movie short in competition here at the Sundance Film Festival, 35-year-old filmmaker Carlos Puga spent three months embedded with Pat Lowery and The Hell's Satans, the moped gang Lowery founded seven years ago in Richmond, Va. In the film, its members cruise around the city by day, skirting the turf of rival gangs, and party hard by night (one party features a Slip-N-Slide lubricated with vegetable oil). Soon, though, the gang becomes embroiled in a war that escalates from moped vandalism to a hit-and-run with a car, and finally culminates in the detonation of a homemade bomb. It's hardcore stuff, and I believed every minute of it — almost.

After all, this entertaining 19-minute film screens in one of the festival's two documentary showcases, and I hadn't done any research prior to seeing it. Also, apparently, I'm gullible. Turns out, Satan Since 2003 isn't so much a documentary as a mockumentary — though even that term, as Puga points out, isn't entirely accurate. "I wanted to keep people guessing what part was fake and what part was real," he says. "It's not a real mockumentary in the sense that I'm shooting real people in real-life situations." The Hell's Satans, for instance, are a real gang — no actors here. But are they violent and engaged in gang warfare? Not so much. That's why Puga prefers to call his film a "doc hybrid."

Satan Since 2003 is part of a growing genre of movies — Catfish and I'm Still Here being the most prominent — that blur the line between fact and fiction. But unlike the directors of those films, Puga has no interest in playing coy. He's happy to divulge exactly where his film diverges from the truth, though he's also quick to note that there's no such thing as a true, objective documentary. "My take on it is, when you're filming somebody and you're editing it and putting it together and making a film, no matter what you call it you're inherently manipulating it in some way. So even if I were to make a full, straight-up doc about The Hell's Satans, it would never be their reality because I would have to figure out some way to make a story out of it, and figure out a way to make it interesting, and cut little snippets of their lives together. I figure if you're never going to get a true documentary, you might as well inject it with a little fun and get a more interesting story out of it."

Puga's day job requires a much different approach. Since 2003, the New York resident has been directing episodes of the MTV series True Life, which requires him to spend months at a time with subjects, waiting for interesting material. "We're not allowed to fake anything," he says. "We're not allowed to have people do anything. We're just shooting, shooting, shooting, hoping for good stuff to happen. So I figured if I could just ask people to do one or two little tiny things, that would make everything come together. We would do it so much faster, and it would be so much more interesting if I could fake a couple of little things here and there. Which is frustrating because you can't do that on the show that I work on. [Satan Since 2003] was my way to release all of that pent-up annoyance at not being able to ... just sitting there with a camera for weeks on end, without anything happening."

Satan Since 2003 started as a trailer Puga used to pitch a mockumentary series for cable TV. There was interest. He found an agent, and meetings were held. But then he had second thoughts. "I just found that whole process to not be fulfiling at all," Puga says, "and then I realized, 'If this project does get picked up, do I really want to spend the next five years of my life doing this?'"

No, he decided.

"I think my next project will be a narrative feature," he says.