Gunma-chan, Uncle Akio, Aoma, and Meemi visit Gunma's kofun site and wander into an alternate world beneath Gunma in the Season 2 finale.
Naha-naha-naha-naha-naha!
¡Naha-naha-naha-naha-naha!
¡Naha-naha-naha-naha-naha!
Nahanahanahanahanaha!
Naha-Naha, Naha-Naha-Naha!