Corrected entry: According to Emmet brown, if someone meet with his alternate ego, it will faint or create a "time paradox" that will destroy time, however Biff talks and interact with his alternate ego with no problem.
Phixius
5th Nov 2006
Back to the Future Part II (1989)
12th Jan 2004
Back to the Future Part II (1989)
Corrected entry: You have to really listen carefully but when the Doc says "Griff's gonna ask you about tonight" he says "Biff" by accident. (00:08:45)
Correction: First, Doc says this as a warning to Marty; that it *may* happen, not that it *must*. Second, Biff *does* create a time paradox that destroys time. That's why there is an alternate 1985 when Doc and Marty go back. Biff has destroyed the original timeline.
Phixius ★
Young Biff doesn't realise he's interacting with himself. He says Old Biff "Claimed to be a distant relative, but that he doesn't see any resemblance."