[...Dammit, if only he was still in Goldenrod! That would have been hilarious to watch!]

That's correct. It's certainly amusing. From what I've seen, there are well over two hundred variations of these creatures; most of them seem to have some sort of "evolution" that allows them to grow stronger. In order to go up against the Elite Four, you must defeat the Gym Leaders - they're also very powerful trainers who specialize in specific "types" of Pokémon. I don't know how powerful they are, though there are several here who have obtained these Gym Badges.