Argus Filch

Argus Filch prowls the corridors of Hogwarts in Harry Potter and the Philosopher's Stone as the school caretaker, a wheezy, sour man with jowls and a lamp, devoted to catching students where they should not be. His constant companion is Mrs Norris, a scrawny, dust-coloured cat with bulging lamplike eyes who patrols on his behalf; students swear the two share some private line of communication, and kicking her is a widely held daydream nobody dares act on. Filch knows the castle's secret passages better than almost anyone, keeps files on troublemakers, and speaks with open nostalgia about the days when punishment meant chains in the dungeons rather than lines. The students' rule of thumb is simple: whatever you are doing, do it somewhere Filch is not.