Chapter 18
The Weighing of the Wands
Harry sat there staring at Snape as the lesson began, picturing horrific things happening to him... If only he knew how to do the Cruciatus Curse... he'd have Snape flat on his back like that spider, jerking and twitching....
pg 300
Chapter 28
Snape’s Worst Memory
Harry looked around and glimpsed Snape a short way away, moving between the tables toward the doors into the entrance hall, still absorbed in his own examination paper. Round-shouldered yet angular, he walked in a twitchy manner that recalled a spider, his oily hair swinging about his face.
pg 643