I got roped into trying to defend one of Hagrid's pets, the hippogriff Buckbeak, on charges that he had savaged Malfoy. That was partly to keep in good with Hagrid, who is useful in many ways, and, I admit, partly to spite Malfoy. I'd seen the whole incident, and Malfoy had deliberately baited the hippogriff. While I agree that Hagrid's not much of a teacher, he is, as I said, useful, and in any case spiting Malfoy's something I'm always up for. The Time-Turner came in very handy for that, particularly after Ron blew up at me because he thought my cat had killed his bloody rat. Of course, when the truth came out, Ron looked stupid. But then, most people are pretty stupid, I find.