Changelings

Changeling is a supernatural creature that takes on the appearance of kidnapped children.

Changelings have been talked about throughout history as being the replacements for real children who are stolen away by fairies or other creatures and fed on. The changeling looks the same as the original child, but is evil in most cases and may abruptly return to the fairy family when older. In Supernatural, it was the changelings who fed on the parents and the real children were locked in cages. Dean and Sam had to burn the fairy "mother" to get rid of all the changelings and rescue the children.

Changelings true form is discolored, slimy skin, hollow eyes and round mouth with many teeth. A changelings true form can be seen only in reflection in a mirror.

The only way to kill a Changeling is by burning them to death with fire.