Faustus was really curious now. Despite what he said, Harry sounded like he was sure he knew things about Hogwarts that Dad didn't. And if Dad didn't know about them, maybe other people didn't too. He knew he'd be coming to Hogwarts next year... this could give him a huge advantage over the other students.
"Okay," he said eagerly. He laughed at Harry's wink and became suddenly quite intense. "Can we prank the Gryffindors as well as the others?"
He didn't really like the way the Gryffindors talked about his Dad. He'd overheard things when he'd been out exploring and when he was coming to and from his lessons with Stephen. The Gryffindors were nasty.