Headcanon that McGonagall is offended on a personal level that Umbridge loves cats.
This literally got 600 more notes just while I was at dinner what the fuck
How has nobody thought about this before tbh
Ok but imagine McGonagall in cat form prowling around the castle, in strategically chosen places so that Umbridge will come across her.
Umbridge takes the cat back to her office and feeds it a little saucer of milk. The cat starts coming back to Umbridge’s office around the same time every night, until eventually Umbridge gets into a little routine of setting out a saucer of milk for the cat before bed.
McGonagall now has all the best secrets on Umbridge, all of the results of the evaluations, and most importantly, is in a perfect position to spy on the ministry for the Order of the Phoenix.
All because Umbridge is obsessed with cats.
The mental image McGonagall lapping up that milk while full of burning hatred for Umbridge amuses me in ways I can hardly describe.