La llorona
http://en.wikipedia.org/wiki/La_llorona
According to this article La llorona killed her children to be with the man she loved and other versions were suggested. I have always heard that La llorona was a beautiful woman who drowned her kids in a lake because her husband cheated on her. Then she killed herself and when her soul was trying to go to heaven god told her to find the bodies of her children. That's why at night you hear her yelling "Ayyyy mis hijos!" which means "oh my children" She hates men and she will try to seduce men and then kill them. There have been reports on "la llorona"