🚨 If you enjoyed this video please LIKE and SUBSCRIBE! 🚨 https://www.youtube.com/channel/UCEjFxmdBapLOX2FbgWUU-BA?sub_confirmation=1 Great Scott, Marty! This Back to the Future Part II fan theory says that Biff Tannen kills Marty McFly in 1955 at the end of the movie. It's not as crazy as it sounds. 👀 Doc Brown is there with his DeLorean to save Marty in the timeline we see in the movie. But in an alternate Back to the Future timeline, Marty McFly wasn't so lucky. This fan theory video explains it all. Discover hidden secrets and share your thoughts in the comments below. For more #InsaneFanTheories, SUBSCRIBE to iDailyIRL here: https://www.youtube.com/channel/UCEjFxmdBapLOX2FbgWUU-BA?view_as=subscriber CLICK HERE for more awesome content: SITE: https://www.idaily.com/movies FACEBOOK: https://www.facebook.com/iDailyIRL/ TWITTER: https://www.twitter.com/iDailyIRL INSTAGRAM: https://www.instagram.com/iDailyIRL SOURCE: https://www.reddit.com/r/FanTheories/comments/31dupf/marty_died_in_that_tunnel_in_bttf2/ CREDITS: "Back to the Future," Universal Pictures "Back to the Future Part II," Universal Pictures