Vätt
Vätt (Swedish, also vätt, vette, vätte) is a household/land spirit synonymous with tomte/nisse, dwelling under houses, barns, rocks, forests. Small, grey-clad, red-capped. Helpful if respected and fed (Christmas porridge with butter); vengeful if neglected. Shapeshifts (goat, horse, goose). Name from ON vættr ('wight'). In Uppland, female gårdsrå parallels it.