My favorite head canon is that Mcgonagall actually had a pet cat that looks EXACTLY like her animagus form and lets it wander around Hogwarts to put all her coworkers on edge
It’s only after it pisses in Snape’s office, jumps up on Flitwick’s lap and starts kneading, and serenely and thoroughly licks its ass in front of Sprout that they begin to suspect. Dumbledore, of course, knew the whole time, and played along–having entire one-sided conversations with it, letting it sit in on meetings McGonagall didn’t particularly feel like attending, and occasionally Charming objects like quills and parchment to make it seem like the cat was grading
MINNY MCGEE STRIKES AGAIN