Hogwarts he is detected using magic in the presence of Muggles, a serious offence among the wizarding community. Dumbledore argued in Harry's defence, stating that it was done in self-defence, and that the Ministry has no authority to expel students – such powers are invested in the Headmaster and the Board of Governors. Snape has attempted to have Harry expelled, and he attempted to have Harry's father, James Potter, expelled when they were at Hogwarts together. The only student known to have been expelled is Hagrid, for the murder of Myrtle with an acromantula believed to be the Monster of Slytherin
Hogwarts staff as the possibility of creating more than one Horcrux. In "Harry Potter and the Deathly Hallows", Slughorn briefly appears with other teachers assembling to fight Death Eaters. As Snape is now Headmaster, Slughorn has again assumed the post of Head of Slytherin. Though he is initially hesitant to join in the Battle of Hogwarts and is assumed to have evacuated with his house, he returns to the fray later on. It is revealed that he has not fled, but has recruited a large number of reinforcements to fight for Hogwarts. He then summons up the courage to duel Voldemort, alongside