Wikipedia
Aoandon
Aoandon, or Aoandō (青行灯 or 青行燈, "blue andon") is a creature illustrated by Toriyama Sekien in his Konjaku Hyakki Shūi. It was meant to represent the spirit that appeared during the game Hyakumonogatari Kaidankai, after the last story was told. The candles in the room during these meetings were often placed in blue-paper andon lamps in order to create an eerie atmosphere, hence this creature's name.
It appears as a human with a blue complexion and twin horns from its brow, and sharp teeth.[4]