The Sceadugenga, or shadow goer, is a fantastical beast which is neither living nor dead, and which can shape shift.
It dwells in the forests of England. In some tales they often take the form of children, acting like Cuckoos by moving into a village and settling down with a compassionate family. They stay to get both food and companionship as they are solitary for the majority of their life.
When they feel like the attachment is too much or when they become bored they often leave to return to the forest.
However, they will stay with humans indefinitely if they fall in love with or form an attachment to a human. Over time, they lose their abilities and forget what they once were, living out the remainder of their existence as a human. If a human became suspicious that the child was a Sceadugenga they need only look at their eyes as the irises were always a pure black with no pigmentation. The first element of the name is from Old English sceaduwe, shadow, and the second elements is likely to be from Old English gong, going or journey, or Old English gan, to go.