This article is about the event. You may be looking for the episode.
“
Said of the second full moon to happen in a single month. Something which occurs only once every few years. It is believed there are ancient spirits that will only be around during a blue moon, and they will answer any and every question about things present, past and future.
A Blue Moon (ブルームーン,Burū Mūn?) occurs when two full moons occur in a month, on the second full moon, a night only once in several years. The magic of a blue moon has the power to reveal many secrets.
Effects
“
The magic of the blue moon may reveal a secret to you.
The entrance to the Blue Moon Abyss can only be seen on the night of a Blue Moon. The apparition in the abyss has knowledge of all things in the past, present, and future, which it may reveal to those who can appease it.