Gekko and the Rotten to the Core Jewel

Gekko and the Rotten to the Core Jewel is the 19th episode of Season 18.

Summary
Gekko begins to act strange when he finds a green jewel that is actually cursed and causes him to become rotten to the core like Mal when her mom gave her a necklace with the same jewel.

Trivia

 * The jewel that Maleficent used to put inside Mal's necklace is seen again in this episode.