In the progressive beginning of the movie,when Doc and Marty are over with their mission in the future, and Marty peers into the shop window, he notices the almanac. But at the top right of the window is a roger rabbit doll. It is shown for only two seconds.

At the time, Robert Zemeckis, the director, was working on "Who Framed Roger Rabbit". His assistant director, Bob Gale put this in while he was on the other movie