A rock doc charts its own course

Now and again, a pop cultural phenomenon breaks boundaries with an energy so furious, it can be mistaken for outrage. It’s not easy to connect the throwers of such pop-cultural hand grenades to a specific agenda; it’s never entirely clear what they want or whether they want anything at all. One thing is clear, though: They are committed to assertion. I thought about that while watching Butt Hole Surfers: The Hole Truth and Nothing Butt, a documentary about a raucous Texas art/punk band that caught fire in the 1980s. The doc left me wondering if it’s even possible to tell where the art ended and the punk began. Whatever the case, it's clear that the Butt Hole Surfers were creative in their craziness, blurring the line between performance art and music in ways that could be both provocative and hilarious. Their show made use of surreal projections, and it's fair to say that they seasoned their weird stew with countercultural zest. Drummer King Coffey was known to pour lighter fluid on…