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This is a genjutsu that reveals the fears that dwell inside people's hearts. Everyone has an image of the one thing they wouldn't want to ever see. This genjutsu is a technique that draws forth such an image from within the heart and has one mistake it for reality. First, an imaginary circle of leaves will spin around and envelop the target, falling away shortly after. After a short period, the illusion will begin. This is to make the illusion more convincing, since the user will likely have moved before the illusion sets in. If the mental image is a gruesome one, the shock will be accordingly great.
The Purizumu clan has a developed use of this Genjutsu called Prismatic Illusion. By centering the chakra through the Gensanryoukyou prism, the jutsu has an improved effect and requires a lesser amount of chakra.