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. They talk about the treasure-trove and the dwarves' intent to reclaim it.
In the movie a parallel is drawn between the eye of Sauron and the eye of Smaug, the two images being juxtaposed. In fact, it is the gaze of Smaug's eye that pressures Bilbo and leads him to take off the ring, with the result that Smaug can see him.
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 noticed a small bare patch on Smaug's jewel-encrusted underbelly, and narrowly escaped.
Smaug couldn't wear it. All he could do is possess it, but a dragon is neither a Man or an Elf, so it wasn't in any way designed for him. I doubt if it would have had any effect on his mind, either. He was fanatically possessive about all his treasure, and the Ring would have been just one more.
Peter Jackson certainly makes the assertion in the theatrical and extended editions of the Hobbit movies that Smaug and Sauron are not only well aware of each other, but are planning to ally with each other. Smaug even seems to have detailed knowledge of Sauron's coming plans.
Smaug could easily have cut through the armies of Mordor, and delayed the invasion of Middle-earth by years. So it wasn't in Sauron's interest to take on the dragon, but that doesn't mean he saw it as a lost cause, as he fully planned on creating an alliance.
Smaug was the last of the great dragons, thus ridding Sauron of a possible powerful ally. Beyond this, all the rest of the dragons in middle earth supposedly only lived far to the north; being now a lesser race, the logistics of bringing them to bear, particularly in the southern campaigns, would be unlikely.
Although both the Balrog and Smaug are creatures of fire, and Gandalf is able to match them thanks to the power of his fire ring, defeating the Balrog takes far more spiritual prowess, which is why Gandalf is able to essentially 'level up' and comes back as Gandalf the White, whereas defeating such an immense physical ...
Smaug was the first human to befall of Eve's powers and turned into a dragon. Smaug was Eve's strongest children and he and the other Alphas lead Eve's monster army.
Though someone could start out with good intentions, the Ring would eventually corrupt them. And that is why Gandalf can't touch it. He is afraid that if he did, it would corrupt him and make him just as bad as Sauron since Sauron put so much of himself and his evil into the One Ring.
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.
Smaug is red and gold, with fiery breath, sharp claws, and a hide as strong as a diamond. Bilbo is horribly afraid, but he works up the nerve to take a single golden cup from one of the piles.
Good question, the answer here lies in linguistics rather than in Middle-Earth lore. Telling Smaug ANYTHING close to the truth is dangerous. He might hate Hobbits, or use that knowledge to follow him back home and destroy him.
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.
Gandalf knew exactly where the Ring was, and who owned it. At any time he could've stepped in to help Bilbo destroy it if he did indeed confirm it was the One Ring. However, Gandalf would also have known how corrupting an influence the Ring can be. So he wouldn't have taken it himself, even if he had known earlier.
Smaug Surpasses Drogon - But Pales in Comparison to GOT's Biggest Dragon. Dragons are an epic part of popular fantasy franchises. Here's how Smaug from The Hobbit compares in size to Game of Thrones' Drogon and Balerion.
Smaug was perhaps one of the dragons that infested the Grey Mountains. Details of his origin are unknown, but he apparently was considered still "young" by himself and Gandalf when he first appeared in Middle-earth's history in T.A. 2770, and as having transitioned to become "old and strong" by T.A. 2941.
Thus, Smaug's embodiment of greed is based in history. From an in-universe perspective, dragons in Middle-earth regularly hoarded gold, and that trait is rooted in their very origin.
Although Smaug was the greatest of the Dragons of his day, he seems not to have been the last of his kind as Gandalf told Frodo Baggins that "there is not now any dragon left on earth in which the old fire is hot enough [to melt the Rings of Power]", indicating the presence of other, lesser dragons.
Basically, no. Drogon is a very young dragon and still barely large enough to get Dany into the sky… Smaug is gigantic, not to mention that Smaug talks and would probably have an intellectual advantage.
The movies didn't show it, but the Balrog all but defeated Gandalf in a battle of spells. So, the bottom line is that some brutish beast like Smaug (regardless of his size) wouldn't have been a threat to a Balrog. The only thing that could save Smaug would be his wings -- if he flew away in full retreat.
Smaug doesn't come close to defeating Sauron. Don't care if Sauron is not a combatant, even in combative strength, he stomps the Golden Dragon. Sauron would destroy Smaug.
Dragons were created by melkor meaning they have the potential of joining Sauron's cause, I believe Gandalf wished that Smaug was out of the picture to prevent Sauron gaining another powerful ally.
As a Valar, Morgoth led a whole slew of Balrogs in the First Age, but because Sauron was only a Maia, the Balrog would have had no loyalty to him. He was his own master in Moria, and no Dark Lord was going to ruin that. Thus, if he really wanted to recruit the Balrog, Sauron would have had to dominate it first.