In Pixar's Cars, the Piston Cup is the fictional racing trophy contested in the film's major championship. Lightning McQueen enters the season-ending race as one of three drivers tied for the lead.
The competition is modeled on stock-car racing, especially the visual language of NASCAR. The Piston Cup season includes multiple races, sponsors, pit crews, and television coverage, giving the animated world a recognizable professional-sports structure.
The finale takes place at the Los Angeles International Speedway, where Lightning races Chick Hicks and The King. Lightning ultimately chooses to help The King after Chick causes a crash, and Chick wins the race while losing the audience's respect.
The Piston Cup should not be confused with the World Grand Prix, which is the international competition in Cars 2. It is also different from the Dinoco sponsorship, a racing brand and prize association that appears throughout the first film.