A Wirey-cow, Wirry-carl etc was in Scotland, a bugbear, goblin, ghost or other frightful object. Sometimes it was used for the Devil, or a scarecrow.

"Draggled sae 'mang muck and stanes,

They looked like wirry-cows" (Allan Ramsay)

The word was used in Scott in Guy Mannering. The word is derived by John Jamieson from "worry" and "to cow" (i.e. "to frighten") , but it seems more likely that the second word is a corruption of "carl" (a man or fellow), and the first word is probably akin to "Urisk" (ùruisg, a brownie). The "urisk" was similar in attributes to the "lubber fiend" of Milton.

Reference

• MacKay, Charles – A Dictionary of Lowland Scotch (1888)