The Devil and Daniel Johnston is a fascinating and lovingly crafted musical documentary that nevertheless misunderstands its own subject. In the 1980s, Daniel Johnston was a creative young geek with a history of mental problems (he was diagnosed as manic-depressive) who found a cult niche with his warbly, faux-childlike, sub–Jonathan Richman ditties. He gave out homemade cassettes, often rerecording an entire tape for each potential fan not because he wanted to, but because he didn't know how to dub. His moonstruck lyrics, mingled with his lack of technique and aura of damaged innocence, helped make him a mascot for the ''outsider'' validity of indie rock, but The Devil and Daniel Johnston presents this haunted footnote as if he were a lost-boy genius on a par with Brian Wilson or the Beatles. That may, of course, be what his fans think, but the bad joke of the movie is that we see Johnston turn himself into a Gen-X icon by merging his open-mike-night novelty act with an unadulterated lust for fame. He's the Chauncey Gardiner of indie rock a mirror of his audience's I-can-be-a-star-too narcissism and the movie's infuriating intrigue is that it all but begs us to turn ourselves into groupies to watch it.