Third Eye Realm

Not neccessarily entirely mythical but there is alot of folklore and mystery as well as romanticism around the subject (Like in some classic disney stories. There is also skepticism about this subject due to the fact that in the past, fraudulent orphanages would pass "autistic" for "feral".

Feral children are said to have been abandoned with little or no human interaction and have suffered a freat deal of abuse, and they have not been conditioned correctly during the age their minds are fragile.. Some have been said to be raised by different animals, most frequently wolves, but there are a wide range of examples. It is also possible that they have been contained in a room for a long time but somehow managed to survive. In an extreme case a child being sold for sexual purposes over and over untill taken for rehabilitation and foster care. She has made several sexual advances, escaped a number of times, and later in life ended up in prison. Many feral children have no empathy for humans  except their own offspring.

They have developed a survival mindset rather than a civil-conformating mindset, they dont understand human morals or emotions. They have greater senses and possibly even physical attributes, such as the ability to run 50mph (in which an army jeep was required for capture).

http://www.feralchildren.com/en/index.php