Petopeto-san(ぺとぺとさん?) is a light novel series by Kou Kimura, with illustrations by Yug. An anime adaptation ran from July 9, 2005 to October 1, 2005. The show takes place in a Japanese school where everything is normal, except for students from what are called "specified races." The specified races are based on yōkai from Japanese mythology; for example, one student on the swim team is a kappa, while another, a nurikabe, merges with walls and is popular in the summertime for having a very cool temperature.
PetoPeto race. Her main source of food is love. With lack of love or food she becomes transparent, which would eventually cause her to disappear. She fears that her race will eventually become extinct. Her mom had three girls before her and all were born insubstantial and faded out soon after birth. Her mom constantly presses her to have a child so she will no longer be in danger of fadeing out too. She is constantly ashamed of sticking to people, claiming that is how her race traps men into being their husbands.