how does smaug die in the hobbit book
Smaug Upon reaching Erebor, the Dwarves sent Bilbo into Smaug's lair, and he was initially successful in stealing a beautiful golden cup as Smaug slept fitfully. Knowing the contents of the treasure hoard which he had slept upon for centuries to the ounce, Smaug quickly realized the cup's absence upon his awakening and sought for the thief on the Mountain. Unsuccessful, he returned to his hoard to lie in wait. Having been nearly killed in the dragon's search, the Dwarves send Bilbo down the secret tunnel a second time. Smaug sensed Bilbo's presence immediately, even though Bilbo had rendered himself invisible with the One Ring, and accused the Hobbit (correctly) of trying to steal from him. During his discourse with the dragon, Bilbo detected a small bare patch in the jewel-encrusted underbelly of the dragon. When Bilbo narrowly escapes an attack from the dragon and collapses amidst the Dwarves at the entrance to the secret tunnel, a thrush overhears Bilbo's frantic retelling of his interaction with the dragon and learns of the bare patch on Smaug's underside. This becomes important later when Bard the Bowman kills the dragon during the dragon's attack on Laketown by shooting an arrow into this bare patch and piercing the dragon mortally.