“Cat Sídhe (Irish: [kat̪ˠ ˈʃiː]) is a fairy creature from Scottish mythology, said to resemble a large black cat with a white spot on its breast. Legend has it that the spectral cat haunts the Scottish Highlands.

A similar creature appears in Edgar Allan Poe's short story, "The Black Cat," in which an ominous feline appears with a white patch on its breast whose shape appears to change into that of the gallows as a means of exacting vengeance on its master for its predecessor's death.

In the Forever Jack novel, by Glenn Hefley, the Cat Sídhe are the guardians of the veil between life and Death.”