Tradition has it that in Appalachian households, when a person died, there was sometimes found in their bed pillow, a closely and mysteriously woven mass of feathers. It was called an Angel Crown, and it indicated that the deceased person had gone to heaven. If such an object was found in the pillow of a sick person, it meant that this person would soon die. In such an instance the crown was called Angel of Death Crown.
Source: Anthony Slayter-Ralph