Brummie's thread about "unwritten prophecies" made me think more broadly about unwritten stuff among JWs. This one is not a prophecy, sounds more like a "urban legend".
There were stories circulating among French JWs in the 70's about people suffering of some unexplained illness, until strange demonic "artworks" were discovered in the feathers of their pillows. Some were almost dying as the "work" was almost completed. When the pillows were burnt the people were instantly cured (no kidding).
I remember an elderly "sister" telling such stories one night. My younger stepsister was scared, and when she went to bed she naturally heard noise in her pillow. I took her pillow in my room and everybody slept all right.
Some time later, my stepmother was ill (actually she had a serious depression but would not admit it as it sounded "unspiritual"). One day she had my father take out all the pillows in the house and open them to find out if there was something abnormal (there wasn't).
Many years later, I happened to mention this to a friend of mine who was reared in a Pentecostal family (his father was a pastor). He stared at me and told me he had heard exactly the same stories in his church. (Quite funny when you think of how JWs and Pentecostals consider each other.)
Ever heard of something similar?