While being stranded in 1955, Marty discovers that Doc’s trapped in 1885 and is killed by Budford “mad dog” Tannen, Biffs great-grandfather. By the help with 1955 Doc, they were able to get Marty back to 1885 to save him from getting killed. When in 1885, Marty randomly got attacked by a bear and ended up in his great-great-grandparents house. To avoid telling his great-great-grandparents his real name, he went under a false name. Clint Eastwood.