From Higurashi no Naku Koro Ni, Furude Rika's not-so-imaginary friend. Was not seen until the answer arcs, when she became visible to the entire Hinamizawa crew and attended school with them. Has prominent horns, which didn't seem to bother anyone in Hinamizawa.
Goes "au au au" a lot.
- Early depictions under the Oyashiro-sama tag.