Where does the trope of ghosts looking like sheets come from? Are there any records of sightings or notable fictional accounts, of ghosts looking like that? I can't think of any. Possible explanations: Fake seances 'Haunted' houses (sheets over furniture rising up) ???
@3fc65e69 Another possibility: the sheet is just a shroud. As used for wrapping the bodies of the dead, especially those too poor to afford a coffin, at least in Europe. (Or for Muslim burial.)