After the feeding, Zabini acted as if on a sugar high, smiling a lot, even giggling on occasion. "Stoned" Hermione called it. Then he became quiet and withdrawn. His spiralling mood could be attributed to his head of house, seemingly having it out for him. Even in potions, the Slytherin got reprimanded for the smallest infractions. Harry tried to talk to Severus, but the professor refused to give him detention. When the Gryffindor noticed a disaster about to happen, he threw a beetle-root into a fellow student's cauldron, making Neville's concoction evaporate in a puff of violet smoke.