Freddy Krueger's Sister?
In the episode "Do You know Where Your Children Are" the babysitter finds out that the child locked in the basement Patty is crazy and that Patty isn't really the parents daughter. When she ask where her real parents are her friends explains that her father is a mental patient at the local mental institution and her mother was a Nun who committed suicide.
Could it be possible that this episode tried to say that Amanda Krueger had twins?