Jonathan Katz is neither a doctor nor a cartoon. But he has been known to be one entertaining funnyman. His old show on Comedy Central, "Dr. Katz, Professional Therapist," was perhaps best known for two elements during its six-year run: its squiggly animation and the remarkable list of guests who sat on Dr. Katz's couch, including Ray Romano, Conan O'Brien, Jon Stewart and Louis C.K. Now Katz is back with a new animated show, "Explosion Bus." Like "Dr. Katz," "Explosion Bus" was created by Tom Snyder. The new show co-stars comedian Tom Leopold, whose writing credits including "Seinfeld" and "Cheers."