In J.R.R. Tolkien’s The Hobbit, Bard defeats the dragon Smaug.
Smaug occupies the Lonely Mountain, also called Erebor, after driving out the dwarves who once ruled there. He guards their treasure and attacks Lake-town when Bilbo’s actions reveal that the company has entered the mountain. Bard, a descendant of the old kings of Dale, learns from the thrush that Smaug has a vulnerable bare patch in his armour-like underside.
Bard uses the Black Arrow to strike that weak spot, killing Smaug as the dragon attacks Lake-town. The event changes the political balance of the story: dwarves, elves, and men then contest the treasure, leading to the Battle of Five Armies.
Smaug is distinct from Tolkien’s other dragons. Glaurung belongs to the First Age stories, while Ancalagon appears in the legend of the War of Wrath.