Potter was grinning at him now, stroking Granger’s head, "You know, Mione brewed a batch of Polyjuice in our second year. We were sure you were the Heir of Slytherin and Ron and I transformed into Crabbe and Goyle to interrogate you. The password of the Slytherin common room was "pure-blood’ and you told us you hoped Hermione would be killed. It was super fun."