A Teru Teru Bōzu (てるてる坊主) is a traditional hand-made doll made out of white paper or cloth that supposedly has magical powers to bring good weather. In Japanese, teru means to shine and bōzu means Buddhist priest, monk or boy, and it was a mascot, so to speak, used by Japanese farmers as a sort of prayer for preventing rainy days.
The Teru Teru Bōzu is still very popular today and it’s common for children to make them before field trips and other outdoor activities. If you’re lucky enough to see one, they usually hang on a string outside of windows. And if you see a Teru Teru Bōzu hanging upside down, that means someone is actually praying for rain.