Capaill Uisce

Glashtyn (Manx: glashtin, glashan, glaistyn, glastyn; pronounced /ˈɡlæʃtᵻn/) is a legendary creature from Manx folklore. The word glashtin is thought to derive from Celtic Old Irish: glais, glaise, glas, meaning "stream", or sometimes even the sea.

By some accounts, the glashtin is a goblin that appears out of its aquatic habitat, to come in contact with the island folk; others equate it to the water horse known locally as "cabyll-ushtey".

The two conflicting accounts above can be reconciled by the trick of regarding the Manx glashtin as a shape-shifter. Recent literature embracing this notion claims that the glashtin assumes human form at times, but betrays his identity when he fails to conceal his ears, which are pointed like a horse's. One modern tale relates how a fisherman's daughter outwitted the glashtyn whom she recognized by his horse's ears, resisting his temptation of a strand of pearls dangled in front of her, and holding out till the red cockerel crowed to announce (prematurely) the break of dawn (Matthews & Matthews 2006,). Here it is said that the glashtyn can transform whenever upon a dunghill.

Modern conceptions tend to portray the glashtin as "a handsome, dark man with curly hair and flashing eyes," capable of alluring women with his attractive appearance.

The creature, known under the variant form #Glashan, was known to have great curiosity for women and pester them in rather picaresque manner, and would grab hold and tear off pieces of women's attire.

The shapeshifter rationalization notwithstanding, early collectors of Manx folklore were only able to gather disparate, inconsistent accounts of the glashtin from different sources (exemplified below, under #Joseph Train, #Cabyll ushtey), some making him out to be like the Fenodyree or kindred spirits, while others insisted it was a water-horse. A similar dichotomy is applicable to the Scandinavian nykken.

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Wikipedia