The Consequences of Shakespeare
"'By the pricking of my thumbs, something wicked this way comes,'" Ron intoned in a low, dramatic voice as Professor Snape approached.
"Ron!" Hermione protested. "That isn't funny. He deserves a lot more respect from you."
Ron merely grinned until he felt Snape's bony fingers on his shoulder. "Five points to Gryffindor for actually knowing any Shakespeare, Mr. Weasley," the professor said smoothly. "Fifty taken away for disrespect. And detention with Filch."
Circling behind Hermione, Snape murmured so that only she could hear. "Two nights' detention with me, Miss Granger, in which we will 'discuss' how wicked I can be."
AN: "something wicked this way comes" was the quote required by the challenge.