The Untold Dragons:

Few people know that the creature that in the film "The Hobbit" is called a dragon is actually a whirlwind.
Well, Kembertbach had only enough wings in his hands. I will explain: the whirlpool has only one, the rear pair of limbs, and instead of the front - cross wings.

Viverna, in addition to having only 2 pairs of limbs, is distinguished by a snake neck, a long tail with a tail, in some conceptions a smaller ( Snake) peel (or even smoother skin), a lack of intelligence and is a poisonous, not a fire-blowing creature. In addition, it is believed that the spirits are much smaller, and are lower dragon-like. And yes, they do not love gold, but fresh and not very meat.
So the fire-breathing, quite intelligent Smog with unbreakable scaly and titanic dimensions and age, it is more likely to be a dragon, even without front legs.