Slughorn was described as a good teacher, but chose favourites out of the classes that he taught, sometimes for their ambition or their brains, sometimes for their charm or their talent, and he had an uncanny knack for choosing those who would go on to become outstanding in their various fields. Horace formed a club named the "Slug Club", of which his favourites were members with himself at the centre, making introductions, forging useful contacts between members, and always reaping some kind of benefit in return. Among them were Tom Riddle, Gwenog Jones, Ambrosius Flume, Dirk Cresswell, Lucius Malfoy and, one of his absolute favourites, Lily Evans.