Quote from : Harry Potter and the Order of the Phoenix Book

The fireworks continued to burn and spread all over the school that afternoon. Though they caused plenty of disruption, the other teachers did not seem to mind them very much. "Dear, dear," said Professor McGonagall sardonically, as one of the dragons soared around her classroom, emitting loud bangs and exhaling flame. "Miss Brown, would you mind running along to the headmistress and informing her that we have an escaped firework in our classroom?" "Thank you so much, Professor!" said Professor Flitwick in his squeaky little voice. "I could have got rid of the sparklers myself, of course, but I wasn't sure whether I had the authority..." Beaming, he closed the classroom door in Umbridge's snarling face.