In Scandinavian folklore, the mylingar were the phantasmal incarnations of the souls of children that had been forced to roam the earth until they could persuade someone (or otherwise cause enough of a ruckus to make their wishes known) to bury them properly. Lore. The myling comes into existence when a child is unwanted and therefore killed by its mother. It can be heard singing in the night, thereby revealing the mother's crime. Ways to help the myling is to give it a name or to find the corpse and bury it in holy soil.
https://en.wikipedia.org/wiki/Myling