Also known as: 裏世界ピクニック, otherside_picnic
A sci-fi/fantasy novel series authored by Miyazawa Iori, with a manga illustrated by Mizuno Eita. A Winter 2021 anime was produced by Liden Films and Felix Film.
The premise involves a pair of university students, Kamikoshi Sorawo and Nishina Toriko, exploring a parallel world known as the Otherside, where various entities based on urban legends and folklore can be found.