Changeling substitution

Dwarf

The Frisian dwarfs are the most domestic and the most troublesome: they fall in love with mortal women and steal them, take children and leave changelings, and at the same time lend and borrow pots, plates, and money — charging interest — help build churches, haul mired carts free, and carry pancakes out to people working the fields.

Changeling

Sources describe fairies, or in some regional tellings witches or other supernatural beings, as covetous of robust, well-favored human children, which they were said to steal, usually before the child could be baptized, leaving one of their own sickly or ill-favored offspring in its place.