Changeling

In the broad folkloric cosmology presented in the sources, various nonhuman peoples (fairies, trolls, nereids, demons and similar groups) interact with human families and sometimes abduct humans—especially infants—and leave one of their own or an enchanted object in the human's place. The substitution may serve multiple motives attributed in the traditions: to obtain servants, to have human children raised by the otherworld, out of malice, or because human beauty or other desirable traits attract otherworldly attention. The changeling thus arises as an exchange enacted by those nonhuman communities within domestic life.

Accounts vary by region. Changelings are generally human-like but often sickly and failing to grow at a normal rate; Irish legends mention beards or long teeth and uncanny intelligence. German names such as Kielkopf or Dickkopf point to reports of unusually large heads or necks. In some stories the replacement is not a living creature but an enchanted object (a 'stock' or log) or an elderly otherworldly person left in place of an infant. Appearance therefore ranges from infantile-but-failing-to-thrive, to oddly aged, to physically deviant in small ways.

Changelings typically display behaviors and traits that mark them as other: failure to thrive or normal growth, ravenous appetite, unusual or uncanny intelligence and perceptiveness, and behavior that may reveal its nature when it believes itself unobserved (jumping, dancing, or playing instruments in Irish and Scottish accounts). Some changelings forget their nonhuman origin and live within human families; others may remember and return to their own people, leaving the human family. The phenomenon is presented functionally as substitution rather than as a defined set of magical powers.