Arbok

This is the final evolutionary step for Ekans, and it is rumored that the ferocious warning markings on Arbok's belly differ from region to region. Arbok is a deadly Pokemon in the wrong hands, and Jesse of Team Rocket definitely has the wrong hands. In "Dig Those Diglett," Jesse's Ekans finally evolves into the powerful Arbok, bringing tears of joy to the nasty villain's eyes.

First appearance: Episode 31—"Dig Those Diglett"