Horace Slughorn is the long-serving Potions teacher and Head of Slytherin House since at least the 1940s, until his retirement after the 1981–82 school year. Following his retirement and the resurgence of Voldemort, Slughorn goes into hiding, concealing all knowledge of his whereabouts from both sides in the growing conflict in the wizarding world. However, after moving Snape to Defence Against the Dark Arts, Dumbledore locates Slughorn and uses Harry as incentive to convince him to return to teaching Potions. Slughorn is described as preferring to be a "back-seat driver", obtaining things he desires by using his contacts, particularly students whom he has invited into the "Slug Club", a group of students favoured by Slughorn, based either on their connections to important people (a type of cronyism) or on his belief that they have talents that will make them important and famous themselves when they leave school (meritocracy). He is one of the first Slytherin characters to defy the house's stereotype and being portrayed in a somewhat positive light: while he is self-serving and not above bending rules, he lacks the near-amorality and underhandedness that had, until that point, been a hallmark of the house. He does not resent blood status in general, and admits a pleasurable surprise when he comes upon a talented Muggle-born, such as Hermione or, years before, Harry's mother Lily Potter, one of his all-time favourite pupils. Also, Slughorn notably displays not pride, but shame at having helped a young Tom Marvolo Riddle perform some of his most noted and impressive feats of magic, as Riddle had questioned Slughorn about Horcruxes. However, students he deems unimportant he ignores, as though they were not there.