Dungeons and Dragons
Changelings
The good people love to plat tricks on mortals; sometimes what seems to have been an accident was actually caused by a mischievous, invisible fairy. In this pursuit the pixies and the sprites are particularly notorious.
A cruel and well-known, if uncommon, prank to steal a human or demi-human baby from its crib and replace it with a shapechanged fairy or a log enchanted to seem a sickly, malformed child, and soon thereafter a dead one. Both the fairy substitute and the child taken are known as changelings. Folklore is full of advice on how to trick changelings into exposes themselves.
Stolen children are given second sight (or perhaps their were taken on account of being born with it) and raised among fairies.
Some have hypothesized that human children are stolen in hopes that they will attain immortality in the sphere of matter, which in this era is restricted to humans, and will play some important part in the long evolution toward the next age of the multiverse.
Most people think that faries are just whimsical and incomprehensible; the stealing of children by some makes about as little sense as the helpful housekeeping of others.
The above information was taken from the Dungeons and Dragon’s Creature Crucible, Tall Tales of the Wee Folk . All of this information here has been copyrighted to TSR Inc and Wizards of the Coast.