Tracy Morgan, when on Saturday Night Live, was often stuck in the black actor roles of “Guy in Background” or “African-American Celebrity,” but he truly excelled at two characters: the easily frightened and reality-averse Brian Fellow, host of Brian Fellow’s Safari Planet, and a gentle, incoherent homeless man who lived in the sewer and rescued overwhelmed celebrities from the obligations of fame. His gift for swinging back and forth between innocent and maniacal has been put to good use on 30 Rock. His fictional character, Tracy Jordan, was once featured in a montage of painfully awkward television appearances he’d made — spliced into the montage was real footage of Morgan himself, making viewers and talk show hosts uncomfortable time and time again. His stage show tends to follow this pattern. At times aggressively offensive (he suffered mass walkouts during a recent Carnegie Hall performance), Morgan focuses on the bawdy and scatological. But there’s always the chance the maniac could pendulum back to the innocent: He famously broke down in tears during an interview with NPR’s Terry Gross when discussing his difficult childhood.