Mahou Shoujo Nante Mou Ii Desukara.

Yuzuka Hanami is an average girl, with a few friends until one day she finds a strange creature named Miton digging through the garbage. Miton suspiciously tells Yuzuka that she has the makings of a magical girl. However, much to her dismay, when she transforms, Yuzuka is wearing a bathing suit.