Buford "Biff" Howard Tannen is the main antagonist of the Back to the Future trilogy, serving as the main antagonist in Back to the Future and Back to the Future Part II and a minor character in Back to the Future Part III.
Biff is the bully of George McFly, both in high school and in adulthood, and is in "love" with Lorraine McFly. He was the great-grandson of Buford "Mad Dog" Tannen and future grandfather to Griff Tannen. He is also the archenemy of Marty McFly, George McFly, Doc Brown and Lorraine Baines.