This is a story my Aunt and my Mother shared with our family:

My parents rented a furnished, large old house. The house was heated by coal. It also had a large piano in the entryway. My father worked the night shift so my Aunt would stay overnight with my Mother to help her care for the new baby.

In the middle of the night when the coal furnace in the basement needed refueling, my Aunt and my Mother would go down together to shovel coal into the furnace. The weird part - when they got back into bed and under their warm covers, the piano would start randomly plunking ALL BY ITSELF. This happened almost every night that they lived there. There were no pets or anyone else living in the house.

Yes, this terrified them as you can imagine. It gets weirder. When my father came home from work, the next morning he would find small lumps of coal on the keyboard. Mother would clean the coal pieces and they would reappear the next day. Needless to say, this was a VERY short term rental for Mom and Dad.

When I lived in Alabama, My friend lived in a duplex. The one side was condemned but they tore a hole in the middle and used to go back there..we used to hear people in the bathroom and when you would open the door we saw someone run at the door but it was like a shadow..really weird :)