In stories (folklore), a changeling is the child of a troll, elf, or fairy that has been left in the place of a human child. The stolen human child then lives with the troll family. A changeling is like a human baby but ugly, always hungry, and with a bad temper. Sometimes the changelings are much wiser than a human baby would be.
It is thought that changeling stories came from actual events. A family who had a handicapped or sick child may have traded their sick child for a healthier, better-looking child.
Folklore says that it might be possible for parents to figure out that their child has been replaced with a changeling. If they discovered the changeling quickly enough, they could get their human child back. One way to get the child back was to put the changeling in an oven. Another way was to put the changeling in a forest so that the troll could take its child back. Sometimes children died in the oven or forest.