Who were the Bogs? Were they those creatures who looked a bit like monsters? The ones who had a line about bringign the peanut butter jars during the end credits?
According to the Internet Movie Database, he did perform Bogg as well as Mr. Knack. It is weird that he was a regular performer on that show, as I've read that he stopped performing to become a writer in 1984, yet he has continued to perform, in such a major role on Eureekas castle and in other Henson productions, like Dog City (He performed Bruno), the 1993-1994 season of Sesame Street, and occassionally on The Wubbulous World of Dr. Seuss, yet I don't know what he has written.