The last moments of Mrs. Norris, Nearly Headless Nick, and the students before they got petrified by the Basilisk.

"So that's little Scorpius. Make sure you beat him in every test, Rosie. Thank God you inherited your mother's brains. Try not to get too friendly with him, though. Your grandfather would never forgive you for marrying a pure-blood." Those words would stay in Rose Weasley's mind for the rest of her school years. Romance in later Hogwarts years.