What is the name of the three headed dog in Harry Potter and the Sorcerer's Stone?

Fluffy is the three-headed dog Hagrid owns in Harry Potter and the Sorcerer’s Stone, tasked with guarding the trapdoor that leads to the Sorcerer’s (Philosopher’s) Stone. Harry, Ron, and Hermione discover that music puts Fluffy to sleep—Harry uses a flute—allowing them to get past. The other options don’t appear as names of magical creatures in the story. J.K. Rowling likely drew on the Greek myth of Cerberus, the multiheaded hound guarding the underworld; Hagrid even says he got Fluffy from a “Greek chappie.” The cutesy name contrasts humorously with the beast’s ferocity. Memory tip: Fluffy falls asleep to a flute—two F’s—so “Fluffy” is the right answer.