- "Crazy drunken driver..."
Red was a street bum that resided in downtown Hill Valley in 1985, and was known to spend the night listening to the radio while lying on a bus stop bench with an advertisement for California raisins on it.
On October 26, 1985, after Marty McFly drove back to his present day in the DeLorean time machine and crashed into the Assembly of Christ, Red woke up, saw this and commented on him being a "crazy drunk driver". Marty apparently knows him, if not happy to see him upon his return. He was also present in 1985A with no improvement as expected. In this alternate reality, Marty bumped into him outside a nightclub (named Sin) and Red, not recognizing him, yelled; "Watch where you're goin', you crazy drunk pedestrian!!".
Behind the scenes
It is disputed whether this is former mayor Red Thomas, but has been generally accepted that he is not. According to Bob Gale's commentary on the Back to the Future DVD set, the name of the bum was ad-libbed by Michael J. Fox. Gale also commented that the photo of the mayor in 1955 on the side of the campaign van was that of set decorator Hal Gausman, whereas the bum was played by George Flower.