Merlin: Season 3, Episode 3

3 - 3: Goblin's Gold

Merlin stumbles upon a secret room in the castle's library and accidentally releases the mischievous goblin trapped inside. The goblin brings chaos to Camelot as the King goes bald overnight and Arthur and Gwen embarrass themselves in front of one another. Soon, the goblin posesses Gaius, who suddenly thirsts for gold and ale and turns Arthur into a donkey. Will Merlin capture the goblin and set things right before serious damage is done?