The Green Ribbon is an illustrated children's horror story from a written series called In a Dark, Dark Room. I would read this in my school library all the time, but haven't seen it for years. I'm glad it was uploaded to YouTube, but beware of the obnoxious jumpscare edited into the video after the story ends, at 2:13.
The story is about a little girl named Jenny, who always has a green ribbon tied around her neck. When people ask her why she wears the ribbon, she tells them it's not important. She goes through most of her life with the ribbon tied on securly, but one day, someone removes the ribbon. Can you guess what happens next?