アキカン!

High schooler Kakeru Daichi buys what looks like an ordinary can of melon soda, only for it to transform into a beautiful, standoffish girl he starts calling Melon. More of these sentient cans, called Akikan, begin turning up, each needing carbon dioxide from a kiss to hold its human form. Melon is a steel can, and Kakeru lands in the middle of the Akikan Elect, a contest staged to settle whether steel or aluminium makes the better container. This light novel is the original source for the Akikan! manga and anime.