Tsuujou Kougeki ga Zentai Kougeki de Ni-kai Kougeki no Okaasan wa Suki desu ka? Namiuchigiwa no Okaasan wa Suki desu ka?
English name: Do You Love Your Mom and Her Two-Hit Multi-Target Attacks? Do You Love Your Mom on the Shore?
Genres: Comedy, Fantasy, Ecchi
Type: OVA, Episodes: 1
Aired: Mar 25, 2020
Studio: J.C.Staff
Source: Light novel
Rating: PG-13 - Teens 13 or older
Synopsis:
Unaired 13th episode.

To thank the group for all their hard work in the past, Shirase invites the party to enjoy the sunny beach. While enjoying the wonderful weather and pristine waters, an accident causes Masato to lose all his memories, including those of Mamako!

(Source: Funimation)