Proctology (Cars, 2006)
Back to Cars for a very different kind of joke about bodily functions. In one of the saddest moments in the Cars franchise, Lightning McQueen barges in on the sheriff (Michael Wallis) as he receives the car equivalent of a trip to the proctologist, courtesy of Doc Hudson (Paul Newman).
P.S.: Here’s an anecdote about Owen Wilson and Paul Newman having a forgettable lunch together during the Cars press tour.