Watch: Trailer For Casey Affleck's 'I'm Still Here' Documentary About Joaquin Phoenix

An art prank? Some kind of mockumentary, you say? Judge for yourself. Here's the trailer to the Casey Affleck-directed documentary, "I'm Still Here" about the turbulent months in Joaquin Phoenix's life when he decided to quit acting, become a rapper, and go further off the rails than he has before (Phoenix has always been an odd duck).

It's really just a teaser trailer, but hey, it's something and that shot of Phoenix's gastropod-like gut rolling over the waist of his pants is grotesque enough to keep us very, very intrigued. The film hits theaters September 10, 2010, and will hit VOD on September 24. Here's the official synopsis:

The directorial debut of Oscar-nominated actor Casey Affleck, I’M STILL HERE is a striking portrayal of a tumultuous year in the life of internationally acclaimed actor Joaquin Phoenix. With remarkable access, I’M STILL HERE follows the Oscar-nominee as he announces his retirement from a successful film career in the fall of 2008 and sets off to reinvent himself as a hip hop musician. Sometimes funny, sometimes shocking, and always riveting, the film is a portrait of an artist at a crossroads. Defying expectations, it deftly explores notions of courage and creative reinvention, as well as the ramifications of a life spent in the public eye.

"I'm Still Here: The Lost Year of Joaquin Phoenix," comes out via Magnolia Pictures but will premiere at the Venice Film Festival earlier in September. Some crazy things happen in this documentary, and don't judge, but Affleck was hit with two sexual harassment suits stemming from the period he was making the film (though two of his female producers are have spoken out in his defense).