¡°Nox,¡± they whispered together, and the lights at the end of their wands went out. Only one door was open. As they crept toward it, they heard movement from behind it; a low moan, and then a deep, loud purring. They exchanged a last look, a last nod.
¡°This is the weirdest thing we've ever done,¡± Harry said fervently.
The Prisoner of Azkaban
¡°He says he is feeling too ill to teach today,¡± said Snape with a twisted smile. ¡°I believe I told you to sit down?¡±