The Mighty Boosh (2004)

S2E5 The Legend of Old Gregg

After a lackluster performance, the group opts to leave town for a while. They head to Black Lake for some fishing, but when Howard grows frustrated with Vince's luck, he sends him off to the nearby pub. While Vince enjoys swapping stories with the locals at the King Prawn's Head, Howard encounters Old Gregg, the strange merman who lurks in the depths of the lake, and is unexpectedly taken by him.