I never saw any Harry Potter movies or read the books, but I’ve heard about a mythologic monster in some of the stories. The monster is a six headed, long fanged black dog that guards an entrance.
That may be what this thief felt as though he was being attacked by.
Dont steal. Dont break into other folks homes.
Cerberus is much older than any Harry Potter tale. It is the beast which guarded Hades in Greek lore.
IIRC, Hagrid had named him “Fluffy”
Greek mythology reference. Cerebus is the guardian of the gates to the underworld.