Here we go; I knew that Robin Williams must have been good at something. And apparently that thing is raunchy, dark comedy. His new movie World's Greatest Dad looks…wow. You wonder how a person can go from a Disney family movie (Old Dogs) to a Bobcat Goldthwaite movie (he spawned the cult classic Shakes the Clown). This was an official selection at Sundance 2009 and was raved by critics as you see in the trailer. Check out the poster and red-band preview below and get psyched, World's Greatest Dad is the classic Williams movie you've been waiting for since the oh so dreadful RV.