Horace Slughorn, the latest hire at Hogwarts in "Harry Potter and the Half-Blood Prince,"  likes to drink. A lot. And he has a habit of inviting students to his quarters. And he's taken a special interest in Harry Potter. All of these add up to what should be a bevy of concerned parents.

J.K. Rowling may not have said as much outright in her book (but it is pretty long, and therefore boring), but we think we have an idea what was going on in Slughorn's skull. Bad touch, Harry, bad touch!