The Bogle (Bogey Man) is a type of Scottish/Northumbrian folkloric creature. One particular Bogle, Shellycoat, is somewhat of a trickster, preferring to confuse and frighten its victims instead of using violence. Shellycoat wears — you might suspect — a coat of sea-shells adorned with seaweed. Shellycoat is known to play games with sailors in the fog, mostly up and around the Scottish rivers and streams. Old Shelly will sometimes fake a call for distress and see how long it can coax people through the fog until they turn around, and is often known for letting loose a grating laugh once its victims give up. One might think that Shelly would make a profound internet troll.
Watch the infamous skit of Old Gregg: