Arbok

It's a shame those cool reptilian eyes are lost when Ekans evolves, but at least Arbok gains those badass monster-face markings in its hood, an exaggeration of the warning spots an actual king cobra has on its back. Arbok's pokedex mentions that these markings vary from region to region, and for a while, that was even reflected by the games themselves.

The first three generations gave us subtly different Arboks, until the fourth went straight back to the first design. Arbok hasn't been seen with a new face since, and that's too bad, because these days we have pokemon who come with variable markings or color schemes in the same game. There's a butterfly pokemon now whose wings even differ depending on what actual, real part of the world you're playing from, and it would be really cool if they also did that for Arbok. Anyway, Ekans and Arbok are best known for having been introduced to us as the signature pokemon of Jessie, one of the three lovable main good guy protagonist central heroes who star in The Pocket Monsters Show (check your local cable listings!). We all kind of assumed Jessie and James would hang on to their original pokemon and just keep growing their roster like the nefarious villain, Ash Ketchum, but for some reason they'd eventually just keep cycling them out and never have more than one or two at a time, though they'd at least continue having pokemon like snakes, insects, carnivorous plants and other less cutesy-poo fare.

What was up with Arbok's pronunciation of its name, though? "CHAH-bok?"