The Nidagrísur is little, thick and rounded, like a little child in swaddling clothes or a big ball of yarn, and of a dark reddish-brown colour. It is said to appear where new-born illegitimate children have been killed and buried without receiving a name. It lies and rolls about before men’s feet to lead them astray from the road, and if it gets between anyone’s legs, he will not see another year. In the field of the village of Skáli on Österö stands a stone, called Loddasa-stone, and here a nidagrísur often lay before the feet of those who went that way in the dark, until once a man who was passing and was annoyed by it, grew angry and said “Loddasi there,” upon which it buried itself in the earth beside the stone, and was never seen again, for now it had got a name.
|No Nidagrisurs available online, so here's a picture by John Bauer of a changeling child reared by trolls, 1913|