Pixies, or Piskies to the Cornish, are tiny faeries said to reside in the English West Country, especially Cornwall, Dartmoor, and Devon. They can appear as little green folk adorned with bells, or equally small, dapper old men dressed in white waistcoats, green stockings, and finely polished shoes; some even say pixies can transform themselves into hedgehogs. Regardless of their appearance, pixies love to dance and revel in the dark of night, and it was once traditional in Cornwall to provide a sort of faerie dance floor, known as a 'pisky pow,' on the roof of one's home; although away from human homesteads pixies can be found capering in the shadows of standing stones or on the banks of streams. It's said the sudden overnight appearance of a mushroom ring is evidence of pixies having recently danced in that particular spot.
Pixies live in prehistoric stone structures and raised faerie mounds, and it's a good idea to give these areas a wide berth, because pixies can be a bit prankish at times--and the pranks of pixies tend to have dreadful consequences for mere mortals. These impish faeries are known to lead the unwary astray, and one story out of Devonshire tells of a farmer who couldn't even find his way out of his own fields until he remembered to turn his coat inside out--a common way to combat pixie glamour. Pixies will steal children, too, and are sometimes responsible for replacing a human child with a faerie changeling. Pixies are occasionally helpful in a way similar to brownies, and one Dartmoor story tells of a lucky farmer who every night would find his harvested wheat threshed in the barn--and all he had to do was repay the pixies with a gift of bread and cheese.
Faeries are often conflated with the souls of the dead, and two such conflations exist within pixie lore; Cornish folk believe pixies to be the departed spirits of Britain's prehistoric inhabitants, while in Devon they're said to be the souls of dead children.
So if you find yourself out traveling at night, it's best to turn your coat inside out just in case, and definitely don't follow the sounds of bells--especially if they take you in the direction of ancient standing stones or a lonely stream--lest you be led astray by dangerously playful pixies.