After school Biff went home to his house where Gertrude would berate him for what happened at the dance.
Biff: I'm home grandma!
Gertrude: Biff! There you are! I got a call from your principal that you attempted rape at the dance parking lot and you nearly caused the dance to end early due to the lead singer's hand being injured!
Biff: Actually my friends did that by throwing that punk in the trunk that caused me $300 damage to the car! But he left town for good and not even his uncle Doctor Emmett Brown won't tell me where he is!
Gertrude: That crazy lunatic scientist won't tell anybody anything! Stay away from him Biff or else you'll be in big trouble!
Biff: Whatever grandma!
Gertrude: You're starting to become like your father and will likely end up like him and become a criminal!
Biff: Or be like Uncle Frank and be just a normal jerk and not go down the road to crime!
Gertrude: My god if your grandfather were still alive right now he would beat your butt as worse as I do!
Biff: Yeah well thank heavens grandpa's history!
Gertrude: (slaps him with the newspaper) Don't ever say that Biff! He loved me dearly! My life has been miserable since he left me for Chicago and died! You have no idea how hard it is to raise a kid or two on your own!
Biff: Actually he was a butthead just like you are! He turned you this way! No wonder why the son of the gangster Irving "Kid" Tannen ended up like you just like dad and uncle! You need to get your life straightened out!
Gertrude: I have my life straightened out unlike you!
Biff: Forget it grandma!