Trebek’s first sitcom appearance came in 1988 on "Mama's Family", when Mama used her homespun wisdom to sneak onto "Jeopardy!" as a contestant.

She didn’t have much respect for her fellow brainiacs, either: “Go sit on a tack, you drip!”

https://tvline.com/lists/alex-trebek-dead-best-tv-cameos-cheers-the-x-files-video/alex-trebek-dead-mamas-family/

"MeTV remembers Alex Trebek with special episodes of Mama's Family and Cheers" (https://www.metv.com/stories/metv-remembers-alex-trebek-with-special-episodes-of-mamas-family-and-cheers)