system
Given the following post, respond as if you're commenting on Reddit:
human
[BTTF] How did Biff originally help George and Lorraine McFly get together?

Okay so at the beginning of BTTF Lorraine claims Biff is the reason her and George are together. 

But we later found out they met and fell in love after George fell out of a tree and got hit by Lorraine's father. 

How exactly did Biff play into this? 

Now, after Marty changes things, it's obvious how Biff played a part, as disturbing as it may be. But the only reason Biff showed up at that point in time and tried to force himself on Lorraine is because he was looking for Calvin Klein, whom did not exist in the original timeline.
gpt
Biff was pursuing Lorraine aggressively and George allowed her to claim him as an S.O. to get biff off her back. In the alternate universe she tries to use marty for this purpose but fails and that causes biff to rape and "claim" her, likely getting her pregnant so he could control her.

The real question is what the fuck happens to Biff in the final timeline?