- "Bulletproof vest! (laughs) Great flick! Great frickin' flick! The guy is brilliant!"
- —Biff Tannen
A Fistful of Dollars is a 1964 spaghetti western starring Clint Eastwood as a gunman known as the Man With No Name in the Old West.
On the morning of October 27, 1985-A, Biff Tannen was watching the movie while soaking in a jacuzzi with two women. The scene that Marty McFly watched before encountering Biff was of Clint getting shot and then recovering after revealing he was wearing a "bulletproof vest" made out of a piece of cast iron. 
When Marty faced off with Buford Tannen on September 7, 1885, the scene became an inspiration for him when he bumped into an iron stove, knocking off the door. He would use it to survive the gunshot by Tannen and knock him cold with it (into a pile of manure). In addition, he did this while using the pseudonym "Clint Eastwood" and wearing the same clothes that The Man With No Name did in A Fistful of Dollars.
Behind the scenes
- Fans of both films have pointed out that the 30 second sequence shown in Part II is different from the shootout in the 1964 film. Most notably, the movie that Biff is watching has a closeup of Eastwood, followed by Eastwood falling into barrels after "Ramon" fires some shots, and a zooming in (with music) on a surprised Ramon. In the 1964 film, there is no closeup of Eastwood as he is fired at, multiple times, by Ramon, and even the accompanying music is different. One in-universe explanation would be that nine years after the timeline was skewed, 1964A is already noticeably different than 1964.