This did not happen to me, but to a friend I went to high school and college with. He is a very down to earth guy and I believe him. I'll call him Mark.
Mark's grandmother lived in an old plantation house here in North Carolina, USA. One day after spending the night at his grandmother's house, Mark woke up the next morning feeling a tug on his cover at the bottom of the bed. He felt the covers being adjusted and figured his grandmother had come into the room to check on him. When he opened his eyes to greet his grandmother good morning, he saw instead the figure of a black woman who was wearing an old-fashioned dress. Her hair was covered by a scarf or bandana. She had very shiny or oily skin and was leaning over the bed smoothing the covers. Mark said that he wasn't really frightened but shocked. He told his grandmother about seeing the woman and she told him that she had seen the same woman in the basement one time. She had been in the basement doing some laundry when a large black woman wearing clothes from another era came walking down the steps carrying an armful of laundry. Mark and his grandmother assume that the woman used to live in the plantation house and still shows up from time to time.