Will Schuester
Boxes placed in the choir room turn out to be glitter bombs, which inundate the room and destroy the piano. People throughout the school are vomiting, and Will Schuester (Matthew Morrison) discovers that Sue Sylvester (Jane Lynch) tainted the water supply and sent the bombs. She also firebombs his car. Will gets his revenge by masquerading as Sue's hairdresser and forcibly shaving her head bald.