He joined the band in 1985, after Marty got his truck, when the four of them went on a camping trip. In the original timeline, when Marty didn't own the truck, they took a bus to the campsite instead.
The four of them auditioned on October 25, 1985 for the Battle of the Bands at the Hill Valley High School gymnasium, playing a hard rock version of "The Power of Love". They were rejected, as the head judge thought they were "just too darn loud".
Behind the scenes
- Bobby was played by Robert DeLapp in Back to the Future. His character wasn't given a name in the film's credits. However, in the comic book story Back to the Future: Who Is Marty McFly?, he was given the name Bobby after the actor who played him.