Akikan!

Plot
Akikan (”Empty Can”) is the unlikely story of high school boy Kakeru Daichi, whose can of melon soda magically transforms into a human girl. More "akikan" girls begin appearing, each of them needing to be infused with carbon dioxide from their respective drink types to survive. The akikans were created as part of the 'Akikan Elect' to determine whether steel cans or aluminium cans are superior. The akikans must battle each other until only the strongest type is left standing.

OVA: "Perfection!? The Hot Spring Panic"
Airdate: October 27, 2009

Everyone goes to a hot spring, with Najimi arranging for a cold spring to be prepared for the Akikans. However, Yell and Budoko are a bit objected against Yurika having her way with Najimi and Misaki. Meanwhile, Melon is a little frustrated with Kakeru's idiocy, though later feels a bit lonely. However, everyone gets annoyed with him when he tries to perform a 'body inspection'. Upon returning to the cold spring, they are surprised to find Miku, who had been looking for her owner. She runs off naked, so the other girls decide to look for her, encountering Kizaki while trying to get their clothes sorted. Melon slips on a banana skin and has sushi fall on her, attracting Miku's owner. When Miku spots her, the same thing happens and they both attract a lot of cats. After Najimi gets the cats off of them, Miku runs off again and Melon gives chase, only to be assaulted by Kakeru, who was trying to escape from Otoya. As punishment, he and Goro are tied up while the others return to the springs.