Denpa Onna to Seishun Otoko

Denpa Onna to Seishun Otoko (電波女と青春男, literally "Electric Wave Woman and Youthful Man", "Denpa" or "Electric Wave" being used in Japanese to refer to a person who is crazy or holds odd beliefs, similar to the English term "Tin foil hat") is a Japanese light novel series written by Hitoma Iruma, with illustrations by Buriki. The series includes eight novels released between January 2009 and April 2011, published by ASCII Media Works under their Dengeki Bunko imprint. A manga adaptation started serialization in the October 2010 issue of ASCII Media Works's Dengeki G's Magazine. A 12-episode anime adaptation began airing in Japan in April 2011.

Story
Makoto Niwa meets his first cousin Erio Tōwa at the house of his aunt Meme Tōwa. Erio is no longer enrolled on the register of the school and wears a futon. Erio claims that she is an extraterrestrial lifeform.