The Hedley Kow was the mischievous bogie of Hedley on the Hill, a village near Ebchester in Northumberland. Unlike the malevolent water-hags or the spectral hounds, the Kow was a trickster whose pranks ended in laughter rather than harm — a shape-shifter who could take not only the forms of animals but of ordinary inanimate things.
The story
In one well-loved tale, recorded by the folklorist Joseph Jacobs, an old woman finds a pot of gold by the roadside; but each time she glances down the treasure has changed — gold to silver, silver to iron, iron at last to a plain stone — which then springs up, reveals itself as the Kow, and capers off. In another, the creature disguises itself as a bundle of straw that grows impossibly heavy in a woman's arms before standing up and shuffling away with a snickering, horse-like laugh.
The Kow delighted in such deceptions: overturning milk pails, frightening farm servants, leading travellers astray and imitating their sweethearts' voices, always melting away with its braying laugh once the trick was sprung. It belongs to the great family of British hobgoblins and bogies, household spirits who are tolerated, even half-affectionately remembered, for the chaos they cause.