Greeny

Alexa's Kecleon (Nicknamed Greeny) is a -type Pokémon owned by Alexa. It made its debut in JE089: The Kecleon Caper. It along with its counterpart Reddy like to steal stuff from unsuspecting people and are masters of hide and seek. It got motion sickness and Brock cured it. It spotted Team Rocket make off with Alexa's Jewelery box and swiped it with its tongue. They later are caught by Team Rocket, but escape and use Psybeam to blast off Team Rocket and Alexa gains trust in Greeny again.

Trivia

 * Kecleon was one of two Pokémon from Generation III that made its debut in the anime before Pokémon: Advanced. The other is Wynaut.
 * It is also another Pokémon that debuted before the series was computer-cel drawn.