The tornado theory makes the most sense in terms of characteristics. Physically, obviously some kind of big snake-perhaps a python-would most resemble a dragon. Long tubular shape with scales and rows of teeth, often found in water or swamp. Some snakes also have “horns”, and snakes actually used to have legs (as they evolved from lizards)-anatomically the legs are now vestigial, so you can only observe them in snakes if you dissect them (very small and devolved). I don’t think it’s an accident that the Chinese zodiac also places the dragon closest to the snake in order, as they’re basically the same animal, one real and the other a mythological descendant.