Rachel Nave (demon)
Rachel Nave was a high school friend of Sam's, who was possessed by a demon on Azazel's orders.
In the fantasy world induced for Dean by the Djinn, Sam explains why we and dean barely talk by saying "That's what you said when you snaked my ATM card or when you bailed on my graduation or when you hooked up with Rachel Nave."
Lucifer tells Sam that during his childhood, many people around him were possessed by demons on Azazel's command in order to manipulate and watch over him. He says that one of these was his prom date Rachel.