Wait, Potter's a Girl!

The girl who lived, Harley Potter, arrives at Hogwarts. Old Bat: "You're just like your mother." Pink Toad: "Professor Snape, calm down—we're colleagues, no need to Avada Kedavra..." "Fine, then Sectumsempra." Noseless Egghead: "Did she swallow a firecracker or what?" Old Bat: "Ten points to Miss Potter, make it fifty!"