[Gallagher]

It's something along the lines of if a carp is able to swim up the river and over a waterfall on a legendary mountain, they'll be transformed into a dragon... It's a Chinese myth, so of course it would look like a Chinese dragon like gyarados is. It's called Dragon's Gate, I believe. And for that matter, dratini and dragonair are, I think, some sort of imoogi, so their evolution makes sense as well, when you know the myth.