While it could be down to simple nerves, Bilbo was hesitant to give the dragon his full name. He was well aware of the destruction Smaug could cause and didn't want to give him any hints as to where he may live.
Smaug asks Bilbo's name. Bilbo doesn't want to give Smaug his name for fear of evil spells, but he also doesn't want to refuse Smaug's request for fear of angering the dragon (neither would we). So Bilbo calls himself a number of fancy names – "Barrel-rider" being the primary one.
Realizing that the Lake-men of Esgaroth must have helped the intruders - reinforced by Bilbo calling himself the "Barrel-rider," Smaug resolved to attack and destroy the town as a punitive measure.
He decides to go back down to Smaug and see if he can find his weak spot. Bilbo is invisible because he is wearing his ring, but Smaug can smell him.
Afraid of Smaug, they move on and take shelter in a rock room near the mountain. In this chapter, Bilbo fulfills his destiny as burglar, a characterization by Gandalf that has been puzzling, because you know that Bilbo is not a criminal thief.
Smaug was considered to be the last "great" dragon of Middle-earth. Sauron allied with Smaug and intended to use the dragon's powers against the people of Middle-earth. But before that could happen, Smaug was slain by Bard the Bowman.
Undeniably, Smaug is the Greatest Dragon left in Middle Earth during the Third Age. Yet, he is not the strongest in its history. That title falls to Ancalagon the Black, the largest dragon ever to have existed in Middle-earth.
Bilbo, meanwhile, regrets calling himself “barrel-rider,” since this will cause Smaug to think of Lake-town and to attack it.
'Every Worm Has His Weak Spot'
Bilbo mentions a dragon's typical weak point -- its belly. Smaug responds by rolling over.
Towards the end of An Unexpected Journey, a thrush appears to the Dwarves and it is considered as a sign of hope. The bird flies to the Lonely Mountain and breaks an nut, which wakes Smaug.
Drogon Daenerys Targaryen's mount from Game of Thrones, ended up being 50 meters long, plus or minus 10. Smaug from The Hobbit is a staggering 140 meters long, give or take 15.
So, one glimpse into Smaug's eyes and the Balrog falls under the spell. Even if it's just for a second—a moment of hesitation or distraction, it'd be enough. Smaug would snatch up Durin's Bane and gobble him up with his sword-sharp teeth (and we know swords can kill Balrogs). There you have it.
Smaug Lost Two Legs
The idea was to get the fear through his bulk. In fact, if you go back and look at the first film and the scenes that he was in, he was actually a four-legged dragon because we just had him stomping through Erebor in all of those flashback scenes," Letteri said.
A title given to the Dragon Smaug by the Dwarves of Thorin's Company, using 'Worm' in its older sense of 'Serpent' or 'Dragon'.
Why does Smaug hoard gold/gems? It is in the nature of dragons to do so. Magpies collect shiny objects, trapdoor spiders build trapdoors, and dragons hoard treasure. Morgoth originally bred the dragons as weapons, but some escaped the War of Wrath and became feral, living in the wastes of the north.
Quotes From The Hobbit Chapter 12
Going on from there was the bravest thing he ever did. The tremendous things that happened afterward were as nothing compared to it. He fought the real battle in the tunnel alone, before he ever saw the vast danger that lay in wait."
Yet, with Smaug being a dragon, he may have shared the same traits as real-world reptiles -- most notably, their ability to go long periods without eating. Many reptiles have a form of hibernation called brumation, where they'll slow down to conserve energy over winter and not require any food.
Smaug was the last great fire-drake, but not the last of all. After his death, others of like kind apparently still survived in the world, but none came close to Smaug in power.
Smaug's dragon-fine would not have been hot enough to destroy the One Ring. The malevolence that Sauron put inside of the Ring could only be destroyed in the Cracks of Doom, so Frodo was compelled to make the journey to Mordor.
He represents the wrongful impulse to hoard, to accumulate beyond what one can use and to refuse to share with others. In revenge for the theft of the Arkenstone, he destroys the town of Lake-town (Esgaroth).
Gandalf absolutely could have killed Smaug in a one-on-one fight. The grey wizard fought and defeated the Balrog of Moria, and a dragon was a lesser evil than that. As proof, Morgoth -- the original Dark Lord of Middle-earth -- created and bred dragons to his evil purpose in the First Age.
Smaug was at very least ~180 years old by the time he was slain.
Being a fully-grown dragon, Smaug was both massive and powerful, possessing physical strength capable of crushing stone with ease, as seen by his attack on the Lonely Mountain.