Smaug was a fire breathing dragon in J.R.R Tolkien's novel 'The Hobbit' and Peter Jackson's film of the same
name. He was also known as 'Smaug the Golden' or 'Smaug the Magnificent' by many.
Smaug attacked the Dwarfish kingdom of Erebor and the neighbouring city, Dale, destroying everything. He guarded all the gold present there, as all dragons guard their plunder till they die. During the invasion, one of his scales were knocked off by a Black Arrow, other than which nothing could pierce his hide.
Later, after many years when Thorin Oakenshield's company went to reclaim Erebor, he was awoken and enraged by them and thus set off to destroy the city of Laketown. There, he was killed by Bard the Bowman using a Black Arrow.