Episode 3 of 13. First transmission on Saturday September 25, 2010 (UK)
The official details about the episode are as follows…
3.03 Goblin’s Gold
Merlin stumbles across a secret chamber and accidentally releases a goblin, as the fantasy drama continues. The mischievous creature possesses Gaius, leading the once-wise physician to develop a taste for gold, ale and magical jokes.
With a suddenly bald King and a scourge of flatulence sweeping the Royal household, can Merlin work out what is going on and banish the goblin back to where he came from before any real damage is done?
Merlin is played by Colin Morgan, the voice of the goblin by Mark Williams, Gaius by Richard Wilson and King Uther by Anthony Head.
(and yes there are only two very similar pics!)