When American Horror Story premiered with Murder House, it put a huge twist on the traditional haunted house story. The series took the typical scares and drama that come with the subgenre and added new rules surrounding the ghosts involved. Some of these changes include the spirits physically interacting with the humans and how dying on a particular property guarantees a person's spirit will remain on the premises. In addition, the house's maid, Moira, had her own ability that not only changed her appearance but also revealed a person's true nature.
Source：https://www.cbr.com/american-horror-story-moira-shifting-age-explained/
