Krupps coffee grinder in Back to the Future II: At the end of the first film, Doc Brown digs through Marty’s trash for fuel, which is actually trash itself since Doc purchased a “Mr. Fusion” in the future to turn ordinary garbage into radioactive time travel juice. However, this super high-tech futuristic prop is literally just a coffee grinder. Nothing was even adjusted for its movie debut. It also shows up in Aliens and is used as a big part of the Nostromo spaceship.