Clyde first appeared in the show's pilot episode "Cartman Gets an Anal Probe". He makes his first prominent appearance in the 1999 season 3 episode "Tweek vs. Craig" in which he tells everyone that both Tweek and Craig decided against fighting each other and went home instead. He has medium-brown hair, wears a burgundy coat, grayish-brown trousers, and sometimes wears ocean-blue mittens. In the season 4 (2000) episode "Cartman's Silly Hate Crime 2000", he is nominated as "the second fattest kid in class" besides Cartman, and is chosen to replace him in the sled race. The season 11 (2007) episode "Lice Capades" focuses heavily on Clyde and a group of anthropomorphic lice, who are portrayed as living in a civilized society on Clyde's head. Clyde was so embarrassed when a girl at the doctor's office asked what he was going in for that he said he had AIDS. While originally voicing Clyde without any computer manipulation, Parker now speaks within his normal vocal range while adding a childlike inflection. The recorded audio is then edited with Pro Tools, and the pitch is altered to make the voice sound more like that of a fourth grader. Clyde's birthday is April 10. In "The List", the girls vote him the cutest boy in class, turning him into a superficial ladies' man, though this list is later revealed to have been manipulated by political considerations. Clyde appears in the three-part story arc "", "Mysterion Rises" and "Coon vs. Coon and Friends" as his alter-ego, Mosquito. He is the focus of the episode "Reverse Cowgirl", in which he causes his mother Betsy's death when he fails to put the toilet seat down in their home, causing her to fall in and have her organs ripped out by the pressure. The episode also reveals Clyde's father's name to be Roger, and that he has a sister. It is revealed in "Crack Baby Athletic Association" that Clyde is part Dutch through his mother. In "Mystery of the Urinal Deuce", it is revealed that Clyde had a colostomy at the age of five. In the episode "Quest for Ratings", after the boys resort to sensationalism to garner higher ratings for their school TV news program, Kyle reports that Clyde has only one testicle, though the truth of this is questionable. Despite his friendship with the four main characters, Clyde serves as the main antagonist of the video game "".