A screwdriver was a tool used for turning screws.
When Marty McFly was locked in the trunk of Reginald's Cadillac by Biff Tannen's gang at the Enchantment Under the Sea dance at Hill Valley High School on November 12, 1955, a screwdriver had to be used by Marvin Berry, lead singer of Marvin Berry and the Starlighters, to jimmy open the lid to let Marty out, as Reginald had a tendency to leave the car keys inside the trunk — which he had done so on this occasion.
However, Marvin badly cut his left hand when the screwdriver slipped, and was unable to play the guitar for the rest of the night. Fortunately, Marty gladly stepped in to take Marvin's place.
Behind the scenes
- In the live action segment of the Back to the Future: The Animated Series episode "Brothers", Emmett Brown and Bill Nye showed how to make an electromagnet, using two batteries and a wire wrapped about a screwdriver, in the video encyclopedia entry "E" for Electromagnet.