Pokemon Season 6 - Episode 279 – A Poached Ego!

Team Rocket encounters a poacher who hunts for poison-type Pokémon. When Team Rocket learn that the captured Pokémon include Koffings and Ekans, they decide to free them from the poachers grasp and they release Arbok and Weezing to protect the Ekans and the Koffings. At the end, James gets himself a new Pokémon, Cacnea.