Two OVAs released with the 8th and 10th volumes of the original novel. They fall chronologically between the first and second seasons.
Source: MyAnimeList
Other anime produced by Studio Deen.
Availability may vary by region.
Ma・Ka・Se・Te Tonight (魔・カ・セ・テ Tonight)
Kizuite Zombie-sama, Watashi wa Classmate desu (気づいてゾンビさま、私はクラスメイトです)
Other anime that aired alongside Is This a Zombie? OVA.
