BttF 2 [School Dance]

Back to the Future 2 (1989): After a series of complicated events, Marty finds himself back at the school dance during the events of the first movie to retrieve a future sports almanac from 1950's Biff. Just as he grabs it however, he runs into Biff's goons who follow him into the dance hall. They mistake his first film self for him as he's playing on stage, thus the present Marty has to stop them from hurting his first film self and causing a paradox.

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