Akikan!

Kakeru Daichi purchases a can of Melon soda. When he goes home and drinks it, the can transforms into a girl. Thinking it's all a dream, Kakeru acts perverted in front of this girl, before getting attacked by the girl's powers. Kakeru ends up treating the can rather shoddily due to the conflict in behaviour and leaves her in a cupboard before going to school. When he comes back though, he finds the girl drained of all life due to being low on carbon dioxide, so he kisses her to allow her to live. Kakeru decides to name the girl Melon. They are visited by a man named Hidehiko Otoya who explains that the 'girlish' cans are part of a battle called 'The Akikan Elect' to determine whether steel cans or aluminium cans are superior. Kakeru is seemingly against this, as he doesn't want people to fight needlessly.