Continuity mistake: In many episodes, the word "chef" on Chef's apron goes from lower case to upper case, within the same episode and usually happens instantly between shots with no time for him to change the apron. (00:11:10)
Continuity mistake: Butters' dad's first name changes from Chris to Steve as the series progresses.
Continuity mistake: Whenever you see Mr. Mackey, he has nothing connecting his glasses in the shots showing the front of his face. But in the side of his face shots, you can see he does have a connector.
Answer: He appears in at least 5 other episodes, but usually just as a background character. He can be seen at Cartman's party in "Immaginationland". He was also one of the kids trying out to replace Butters in the "Professor Chaos" episode.
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