Smaug was a dragon in J.R.R. Tolkien's novel The Hobbit during the "Third Age". He heard of the vast accumulation of treasure within the Kingdom of Erebor and descended in fire upon the town of Dale, whence he stole all of the treasure from the Dwarves and lived among them, within the halls of Erebor. The treasure was finally dispersed when Bilbo and the dwarves hid in a tunnel and finally liberated their people from living under his rule by killing the fire dragon who ruled over them.
Smaug was killed in battle above the town of Lake-Town by the last arrow of a famous bowman tipped off about a chink in Smaug's armor by the thrush befriended by Bilbo atop Smaug's Lonely Mountain lair, and for ever after his bones could be seen beneath the waters of Long Lake from the shore beside the town.