Meanwhile, it became clear just how many Skiving Snackboxes Fred and George had managed to sell before leaving Hogwarts. Umbridge only had to enter her classroom for the students assembled there to faint, vomit, develop dangerous fevers or else spout blood from both nostrils. Shrieking with rage and frustration, she attempted to trace the mysterious symptoms to their source, but the students told her stubbornly they were suffering from "Umbridge-itis'. After putting four successive classes in detention and failing to discover their secret, she was forced to give up and allow the bleeding, swooning, sweating and vomiting students to leave her classes in droves.