Touka Gettan Season 1 Episode 18

Sea

When Nene goes to wake Yumiko up in the morning, she finds a large sea right outside the house which is due to Yumiko inadvertently using her powers to change the physical world. At school, the new pool area has opened, and the students get to take a day off, but since Tōka does not like crowded areas, he leaves to go back home without telling anyone. Momoka tries to search for him most of the day at school, but only later finds out he went home. Momoka is transported to the sea by the house via Yumiko's powers and eventually finds Tōka, but both of their swimsuits are either eaten off by fish or dissolve off, again due to Yumiko. In the end, the sea disappears at night before Nene can take a dip.