Doc Brown

Doc Brown was the main protagonist of Back To The Future: The Ride, until it closed to make way for The Simpsons Ride.

Episode One - Back to the Future
Doc was able to track down Biff, who held the Simpson family with immense contempt after the replacement.

He taught Joseph Barnes and Benjamin O'Toole that characters from all forms of media were able to exit such media, and gave Barnes a crucial tool - the camera-recorder, which is able to force the characters back into their films. He took the two back to 2007 in order to stop Biff stopping construction on The Simpsons Ride.