“NO!” shrieked Hermione, and with a deafening blast from her wand, Fenrir Greyback was thrown backward from the feebly stirring body of Lavender Brown. He hit the marble banisters and struggled to return to his feet. Then, with a bright white flash and a crack, a crystal ball fell on top of his head, and he crumpled to the ground and did not move.

“I have more!” shrieked Professor Trelawney from over the banisters. “More for any who want them! Here —”

And with a movement like a tennis serve, she heaved another enormous crystal sphere from her bag, waved her wand through the air, and caused the ball to speed across the hall and smash through a window.

Harry Potter and the Deathly Hallows – J.K. Rowling