Robert Downey Jr for Oz prequel April 21, 2010 Robert Downey Jr. is off to see the wizard! Robert Downey Jr. is reportedly eying the role of the Wizard in Oz The Great And Powerful. The Mitchell Kapner-scripted Oz is a prequel that takes pieces from the original L. Frank Baum Wizard of Oz books. “As conceived in Kapner’s script, the wizard is a charlatan who’s part of a traveling circus but goes on a similar odyssey as Dorothy when he mysteriously lands in Oz,” according to The Los Angeles Times. Sam Mendes is said to be the front runner to direct the project.