This is a freakish spirit who delights rather to perplex and frighten mankind than either to serve or seriously hurt them. The Esprit Follet of the French, Shakespeare’s Puck, or Robin Goodfellow, and Shellycoat, a spirit who resides in the waters, and has given his name to many a rock and stone on the Scottish coast, belong to the class of bogles. One of Shellycoat’s pranks is thus narrated:—Two men in a very dark night, approaching the banks of the Ettrick, heard a doleful voice from its waves repeatedly exclaim, “Lost! lost!” They followed the sound, which seemed to be the voice of a drowning person, and, to their astonishment, found that it ascended the river; still they continued to follow the cry of the malicious sprite, and, arriving before dawn at the very sources of the river, the voice was now heard descending the opposite side of the mountain in which they arise. The fatigued and deluded travellers now relinquished the pursuit, and had no sooner done so, than they heard Shellycoat applauding, in loud bursts of laughter, his successful roguery.
http://english.skazk.ru/catalog/scotland-folktales/the-bogle-929/