Fluffy
Fluffy is a three-headed dog in the Harry Potter series, introduced in "Harry Potter and the Philosopher's Stone." Hagrid, the Hogwarts gamekeeper, acquires Fluffy to guard the trapdoor leading to the Philosopher's Stone. Each of Fluffy's heads corresponds to a different type of music that puts him to sleep: one head likes soft lullabies, another enjoys jazz, and the third prefers rock.
Fluffy is a massive and imposing creature, designed to deter intruders with his sheer size and intimidating appearance. Despite his ferocious exterior, Fluffy has a weakness for music, which clever characters can exploit to their advantage.
Harry, Hermione, and Ron encounter Fluffy during their quest to stop Voldemort from stealing the Philosopher's Stone. They use Hagrid's information about Fluffy's musical preferences to put him to sleep and proceed through the trapdoor, demonstrating that sometimes brains can triumph over brawn.
