I think the last time I saw him in anything was on Jerry Seinfeld's Comedians in Cars Getting Coffee, when he and Mel Brooks were eating TV dinners and watching Jeopardy.I always liked seeing him show up in a TV show as a bit character for an episode or three. It was a reliability thing. Like checking in on a long running machine that didn't really need any maintenance? But you still would look in periodically just to make sure it was going?
I'm not sure how much sense that will make to anyone else.