Seems like a little power has gone to the head girl's noggin. She has taken up two classes with outlandish and disrespectful behavior toward the very patient Hogwarts professors of DADA and History of Magic. It would seem though, that being the head girl has it's priveleges as neither has taken the head girl head on.

Is it possible the head girl knows something about these two that allows her indiscriminate behavior? Perhaps there is some deep, dark secret that helps the Defense of the Dark Arts teacher excel at her craft. Maybe the History of Magic professor has her own 'magical history'. Who's to know.

One thing we do know, if Ms. Alexa Cambridge is not reined in, she may choose to reign over the students and faculty of Hogwarts in place of Headmisstress Anastasia Truebridge.