"Today, we will be transfiguring rubbish into raccoon dogs. Those of you who—" Professor McGonagall’s mouth tightened into a straight line as the door opened again, interrupting her lesson. "That’ll be five points from Slytherin, Mister Malfoy," she said, locking the door with her wand so that none more may enter tardy behind him. "Those of you who perfected this spell last year may resume independent study for your N.E.W.T.s at the back of the class. For those who could use more practice or were not able to attend this part of the curriculum, please move to the front tables and break up into pairs." The eighth year students who’d chosen to return, were no longer divided into classes by their Houses, and instead had been combined into one single class for each advanced subject.