The Ao Andon is a powerful spirit of collective human terror from Japanese mythology that can only manifest after a ritual is performed.
Similar to spirits such as Bloody Mary in other cultures, the ritual involves telling one hundred ghost stories and lighting a candle for each one, placing them each in small paper lanterns.
Each time a story is complete, participants would snuff out a candle, and if the hundredth candle was snuffed out, the Ao Andon would manifest. It is unknown what the ghost would do, as legends claim the ritual seldom (if ever) was completed due to people being too terrified to finish it.
That being said, the creature is often envisioned as a woman with demonic features, glowing bright blue and embodying the collective fears of all involved in summoning her to the physical world.
Some variants believe that instead of being a ghost the Ao Andon is instead a trick played by a kitsune, tanuki or other mischief-prone yokai.