Biff Tannen is a fictional character in the Back to the Future trilogy. Thomas F. Wilson plays Biff in all three films as well as the Universal Studios ride, and voiced the character in the animated series. Aidan Cutler played him in the original West End production of the first film's stage musical adaptation, and Nathaniel Hackmann plays him in the Broadway production. Biff is the main antagonist of the first and second films, while his great-grandfather, Buford "Mad Dog" Tannen (also played by Wilson), is the main antagonist of the third.
Biff is portrayed as a hulking, belligerent, dim-witted bully who obtains what he wants by intimidating others into doing his work for him, or by cheating. He and his family members are shown to misuse idioms in ways that make them appear foolish and comical, despite their intention to insult or intimidate. He frequently calls others "butthead".
Source : Wikipedia
