The dragon in J.R.R. Tolkien’s novel The Hobbit is Smaug.
Smaug is a fire-breathing dragon who takes the Lonely Mountain and its treasure from the Dwarves of Erebor. He drives King Thrór’s people into exile and occupies the mountain for generations. Bilbo Baggins enters Erebor with Thorin Oakenshield’s company to discover a weakness in the dragon’s defenses.
Smaug can speak fluently and is highly intelligent, making his conversations with Bilbo as important as his physical power. Bilbo notices that a bare patch on Smaug’s underside lacks the protective gemstones embedded in the rest of his hide. He reports this weakness to the Men of Lake-town.
Bard the Bowman ultimately kills Smaug with the Black Arrow. Smaug is distinct from Glaurung and Ancalagon, dragons from Tolkien’s earlier First Age stories, and from Scatha, a later dragon slain by Fram.