It's an OVA episode released after the end of the main series. We have seen it countless times already. Highschool of the Dead, Kore Wa Zombie Desu Ka, Deadman Wonderland, Nazo no Kanojo X and a few other OVAs that are completely bullshit and fucking useless to the story. On top of that, Episode 12 of Jashin-chan Dropkick is a fucking beach episode. The most peculiar thing about it is, unlike the OVAs from the series I already used for comparison, this one is surprisingly good. It's probably better than any episode of the main anime by itself. You know, in opposition to the first elevenepisodes with fucking nothing and dumb gags that makes you feel guilty for finding them funny, I'm pretty found of the storyline of this one.

Heck, the thing is: we get some conflict here. And it's more than we already saw before in this anime. It's surprisingly nice to watch. You obviously won't like it if you already don't like the main series, but it's worth a try if you find it at least entertaining.