Original Appearances: Harry Potter and The Philosopher's Stone (US Title: Harry Potter and the Sorcerer's Stone)
Other Appearances: Movie version of the above book
Biography: Hagrid, the Hogwarts gamekeeper, provided Fluffy, a giant three-headed dog to guard the trapdoor leading to the underground chamber where the Philosopher's (Sorcerer's) Stone was hidden. The only way to get past Fluffy was to lull him to sleep by playing music (as was the case with Cerberus, the inspiration for Fluffy). Harry Potter, Ron Weasley, and Hermione Granger first encounter Fluffy when they are trying to hide from Peeves, who was trying to give them away to Argus Filch, who was searching for them. Later, while Fluffy is guarding the Stone, Professor Quirinus Quirrell plays a harp to lull Fluffy to sleep so he can get access to the Stone. Harry gets past Fluffy using a flue that Hagrid gave him.
Powers: Since Fluffy is a gigantic three-headed dog, I don't suppose he needs much else in the way of powers, does he?
Group Affiliation: Hogwarts
Miscellaneous: According to an interview with creator J.K. Rowling about what happened to Fluffy after the first Harry Potter book, she said that Fluffy had been released into the Forbidden Forest.