It was a well-known fact that the Marauders had managed to make McGonagall angry.
One generation later, it was a well-known fact that their only descendent was able to make McGonagall insane.
Dorea Potter winced as her eardrums were nearly ruptured by a loud shriek while she ate her dinner.
"Potter, Weasley, and Weasley! Straight to the Headmaster's Office, the lot of you!" McGonagall shrilled. She had taken the pranks, given detentions, and written home, but this was the last straw—festooning her classroom with CATNIP! It had nearly driven her crazy by the time Filch had removed it all (although she had him deliver it all to her private rooms—it was perfectly good catnip, after all.)
The guilty trio of red-heads exchanged looks with one another, stood, linked arms, and as one began skipping out the door and down the hallway singing,
"We're off to see the wizard, The Wonderful Wizard of Oz
We hear he is a whiz of a wiz, if ever a wiz there was
If ever, oh ever a wiz there was, The Wizard of Oz is one because
Because, because, because, because, because
Because of the wonderful things he does
We're off to see the wizard, The Wonderful Wizard of Oz!"
The Great Hall roared with laughter.
McGonagall slammed her head repeatedly against the table, muttering to herself.
Filius Flitwick looked at her worriedly. He could just make out the words "Catnip…pranks…is this a punishment, James….I'm sorry already!"