Both are half human and half goat nature spirits; and whilst the Glaistig is only depicted as female, the Urisk is both male and female. They both resemble a Faun or Satyr.
Folk tales vary concerning the Glaistig. She is half woman and half goat (lower half) being, living outdoors protecting both wild and domesticated animals. Her long golden hair falls into a green dress that hides these goat legs. She has malevolent, and benevolent characteristics.
Elsewhere in Scotland and due to religious superstition, she became the ‘The Green Lady’, a malevolent spirit associated with castles and other fortified homes, found wandering through woodland, at the side of a river, or near waterfalls, luring travellers to their doom.
Another being with a goat connection is the Urisk. The Urisk is half human and half goat (lower half), with long, often green, hair and sharp claws. In folklore traditions, Urisk is either the progeny from the union of Elf and human, the result of the Fairie’s curse, or one of the Faun.
At one time, many clan chiefs had an Urisk husband and wife as household helpers, and it became quite the fashion to encourage an Urisk to attach itself to one of the ‘great houses’ of Scotland.
Folklore of Scotland 