Troll cat

Witches reportedly were able to create them from "human hair, nails, wood shavings, and the like",[1] and they were said to suck milk from cows and steal cream from households.

[3] The Norwegian names trollnøste and trollnøa indicate their shapes: those troll cats looked like balls of yarn.

[4] Peter Christen Asbjørnsen, a scholar of Norwegian folklore, retells a story in which Gypsies took advantage of farmers' beliefs in troll cats by stealing milk and blaming it on troll cats, a story they would then render believable by digging up a previously buried "bladder filled with red water surrounded by a cat-skin".

The tilberi (also called snakkur, a spindle "made from a dead man's rib, stolen wool, and communion wine") plays the same role as the troll cat.

[1] The slime mold Fuligo septica and the foam made by spittle bugs were seen as troll cat droppings.