This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Each Uisge (Scottish)
The each-uisge, a supernatural water horse found in the Scottish Highlands, has been described as "perhaps the fiercest and most dangerous of all the water-horses" by the folklorist Katharine Briggs.Often mistaken for the kelpie (which inhabits streams and rivers), the each-uisge lives in the sea, sea lochs, and fresh water lochs. The each-uisge is a shape-shifter, disguising itself as a fine horse, pony, a handsome man or an enormous bird such as a boobrie.
If, while in horse form, a man mounts it, he is only safe as long as the each-uisge is ridden in the interior of land. However, the merest glimpse or smell of water means the beginning of the end for the rider. In its human form it is said to appear as a handsome man, and can be recognised as a mythological creature only by the water weeds or profuse sand and mud in its hair. Because of this, people in the Highlands were often wary of lone animals and strangers by the water's edge, near where the each-uisge was reputed to live.