Mrs. Norris

From the Encyclopedia of Speculative Fiction - http://encyclopedia.wizards.pro

Mrs. Norris is Argus Filch's cat. She accompanies him wherever he goes, and sometimes helps him catch students wandering after curfew. Once she spots a wrongdoer, Filch usually arrives within seconds. She is usually called "my sweet" by Filch, but is hated by the students, and by Hagrid, who once remarked that he would like to introduce her to Fang.

Mrs. Norris was once petrified, when she saw a basilisk's reflection in Chamber of Secrets. She was restored to her usual state by Professor Sprout.