The title character in Dog Man is a man with a dog’s head. The product of improvised emergency surgery after a bomb squad mishap, he serves as a police officer in a generic city called “OK City.” Dog Man’s nemesis is a villainous cat named Petey; their ongoing relationship consists of Dog Man repeatedly capturing Petey, and Petey repeatedly escaping from jail. This goes on agreeably enough until Petey decides to up the ante by cloning himself,...