Snakkr

As defined by the Cleasby & Vigfusson Old Norse to English dictionary:

snakkr

m. [akin to snákr, a snake], a snake-formed imp, as described in popular superstition, made of a man’s rib swaddled in wool; then under a wizard’s spell, it was sent out to suck the ewes and cows of his neighbours and to bring home the milk to his master or mistress; butter made of this milk (snakk-smér) breaks up if marked with a cross; the snakkr is also called til-beri (q. v.), Maurer’s Volksagen. There is a similar legend among the Finns, who call the imp ‘para,’ see Ihire’s Diet, and Castren’s Finn. Mythol.

Possible runic inscription in Younger Futhark:ᛋᚾᛅᚴᚴᚱ
Younger Futhark runes were used from 8th to 12th centuries in Scandinavia and their overseas settlements