Petopeto-san (ぺとぺとさん, Petopeto-san?) 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.

Source: Wikipedia