Gray's Sports Almanac was a catalog of sports scores from 1950 to 2000, originally purchased by Marty McFly during his visit to the year 2015 but stolen by the 2015 version of Biff Tannen. Tannen won his first million betting on a horse race in 1958 and through his actions of that timeline, was responsible for the creation of the hellish Biffhorrific Hill Valley. (Back to the Future Part II)