The archetypical gangster, Mad Dog is the leader of a shifty gang of dogs living on the Wrong Side off the tracks. He is narcissistic enough to believe his tattered apartment is first rate, and is willing to harm or kill anyone who challenges his way of life. Because of this, his romance with his girlfriend Bunny isn't always functional, but he is smooth enough to coax her back into his arms every time. He keeps an oversized flower pot in his living room. Talk about fancy.
When Kitty started convincing Bunny to leave Mad Dog, he did what he knew how to do; made her leave town. This caused a great bump in his relationship with Bunny, who unenthusiastically went about the day thinking about nothing but her friend. Eventually, this struck a nerve with Mad Dog, and he threatened to bury both of them if she kept dwelling on it. Afterwards, he tried to comfort her, but she tricked him and attached his collar to the wall so she could leave. His gang caught her, and they buried her up to her head.
Mad Dog left the room, but later heard a crashing upstairs. Bunny was escaping with a purple dog, so Mad Dog gave chase in his car. He almost ran down Bunny when Courage dove through the window and spun the car onto the train tracks. The approaching train totalled the car and left Mad Dog for dead on the train's head.