Changelings
In medieval Britain, parents sometimes believed that their child had been taken away by the fairy people and substituted with a changeling. There were a number of tests to find out. One was to put a shoe in a bowl of soup in front of the baby: if it laughed, showing it understood the joke, it was a fairy. Similarly, if you pretended to try to make a loaf of bread in an eggshell in front of the child and it giggled, it wasn’t human. Suspect babies would be held over a fire to drive the fairies out, or abandoned.
