Smaug is the main villain and dragon in J.R.R. Tolkien’s The Hobbit.
Smaug occupies the Lonely Mountain and guards the treasure that once belonged to the Dwarves of Erebor. He drove them from their kingdom before the events of the novel. Bilbo Baggins enters the mountain as part of Thorin Oakenshield’s company and discovers a weakness in Smaug’s armour: a bare patch on the left side of his chest.
That information reaches Bard of Lake-town, who uses the Black Arrow to kill the dragon. Smaug is sometimes confused with Tolkien’s other dragons. Glaurung appears in The Silmarillion and The Children of Húrin, while Ancalagon the Black belongs to the First Age and is defeated during the War of Wrath. Smaug is specifically the dragon of The Hobbit and the treasure-hoard guardian of Erebor.