Dr. Katz is the main character from Dr. Katz, Professional Therapist. He appeared in the Season Two episode, "Summer Sucks", where he is seeing giving psychotherapy to Mr. Garrison, who was vacationing in New York. Dr. Katz believed that Mr. Hat was a manifestation of Mr. Garrison's homosexuality, which angered Mr. Garrison. Immediately afterwards, a gigantic charcoal snake destroyed part of New York, which also cut a swath of destruction through Dr. Katz's office, smothering him to death. Mr. Garrison, who shielded himself from the charcoal snake and emerged unscathed, felt that Dr. Katz deserved such a fate for his remarks about himself and Mr. Hat.
Dr. Katz wears a yellow button-up shirt and a red tie. He is mostly bald with black hair on the sides and back of his head. He has black eyebrows.
- The outlines of Dr. Katz are squiggly, referencing the "Squigglevision" animation style of the show.
- Coincidentally, a few months after "Summer Sucks" aired, MAD Magazine did a simultaneous parody in which Katz, along with his son Ben and assistant Laura, who is also Ben's girlfriend, moved to South Park and set up a practice in town. Unfortunately, the trials of working and living in South Park, having to listen to head cases like Cartman (whose file contains over 450 folders) and Mr. Garrison, while Ben catches Laura in bed with Chef, quickly leave him questioning his decision, and after a broken pencil starts a chain reaction in which Kenny is decapitated by his framed diploma, he calls his New York clients begging them to take him back.