Minerva McGonagall (5/17)
"I said stop this," Minerva repeats, more forcefully, making her mind go through logical steps. If there were really children in the walls, somehow, she would be able to smell them in her Animagus form, would she not? And that would perhaps set her mind at ease.
Once she's a tabby, she immediately takes note that there aren't unfamiliar people scents- but there are other new things, pungent, that she can't quite place, and a feeling that there is something there, if not a person.
It might not give her an answer, but she meows irritably at the wall nonetheless.