In European Folklore, Changelings are offsprings of fairies or elves who are disabled, unintelligent,or have unexplained diseases, disorders,& have developmental disabilities, whom are substituted human infants.
Changelings can appear human, but their true nature is revealed in reflection. They feed on humans, specifically on synovial fluid.
According to legend changelings won't grow in size of a human child. Legend also says that the human children were given to devil.
