sondenso
Guys, could you tell me what is the right pronoun here and why?
Just between you and (I/me), Marcy's hair is a fright.
For this sentence, I think that "Marcy's hair" is subject, and all others are
NOT the subject.
I flip it: Marcy's hair is a fright just
between you and me!
"Between" is preposition, making "you and me" an objective as group!Honestly, the meaning of this sentence is really funny for me!

Hats off to you Sondenso. That's an elegant explanation.
Sanjay - Marcy's hair IS the subject of the sentence. That's what is being talked about and hence a candidate for the subject.
Also, anything that appears as an object of the preposition (a.k.a the prepositional phrase) can't be the subject of the sentence either.