Troll cat

In the Scandinavian tradition the troll cat is not an autonomous wild spirit but an artificial familiar created and kept by a witch to secure dairy for her. Sources report Norwegian forms made from domestic detritus (e.g., human hair, nails, wood shavings and the like). Closely related but distinct Icelandic accounts identify the tilberi (snakkur), made by a different procedure in Icelandic tales (a spindle made from a dead man's rib, stolen wool, and communion wine); the tilberi is treated as an analogue rather than identical origin to Norwegian troll cat accounts.

Two principal morphologies are recorded: a ball-shaped form described in Norwegian names (trollnøste/trollnøa) as looking like balls of yarn or skeins, and a cat-shaped form that appears as an ordinary cat. Regional variants and summaries also record milk rabbit/milk hare shapes. Some descriptions emphasize their constructed nature, assembled from hair, nails, wood shavings and similar materials. Folktales attribute peculiar physical signs when injured (for example, shooting a troll cat was said to cause milk to spray from its wound).

Troll cats suck milk from cows and lick cream in houses, then spit the stolen milk into the witch's milk pails or into troughs beside the witch's house. They enter homes to lick cream and go to cows to suck milk, functioning as nocturnal or stealthy dairy thieves in rural contexts. Cat-shaped varieties are metaphysically linked to their maker such that harming the familiar can harm the witch; the familiar is also described as remaining bound to its maker after death unless it is buried with her or retrieved from her grave. Natural phenomena (slime mold Fuligo septica, spittle-bug foam, or certain cattle regurgitations) were sometimes interpreted as troll cat droppings in folkloric explanations.