The great dragon Smaug was one of the most dangerous beings in the history of Middle-earth. In The Hobbit, Bilbo and Thorin Oakenshield's Company of Dwarves awoke Smaug from his centuries-long slumber under the Lonely Mountain, and Bard the Bowman slew him with a black arrow. However, this was far from an inevitable outcome. If Bard's aim had not been true, or if the Dwarves had never attempted to reclaim the kingdom of Erebor in the first place, Smaug would have survived The Hobbit, and the events of The Lord of the Rings would have played out very differently.
Source：https://www.cbr.com/the-hobbit-what-if-smaug-survived/
