Itsuka Tenma no Kuro Usagi: Kokoro Utsuri no Toukoubi - School Attendance Day
Japanese title: いつか天魔の黒ウサギ 心移りの登校日 ~すくーる·あてんだんす·でぃ~
Alternative titles: Itsuka Tenma no Kuro Usagi OVA, Itsuka Tenma no Kuro Usagi Episode 13, Itsuka Tenma no Kuro-Usagi OVA, A Dark Rabbit has Seven Lives OVA, Itsuten, Itsu-ten
Type: OVA
Source: Light novel
Episodes: 1
Status: Finished Airing
Aired: Dec 5, 2011
Duration: 24 min
Rating: PG-13 - Teens 13 or older
Studios: Zexcs
Genres: Action, Comedy, Romance, Supernatural, Ecchi
Themes: Mythology, School, Vampire

Episode bundled with the ninth volume of the Itsuka Tenma no Kuro Usagi novel.

Includes Mirai's chibi-style dream, body-swapping and a crossover with Densetsu no Yuusha no Densetsu.