Prism Magical: Prism Generations!(2010)

There is a small town on the sea. Raika just enjoys his school life with Ibuki, his old friend, and Yuri, his maid. However, his father is actually a magical girl (?). Also, a group of magical girls come to his school to look for a treasure stone called Mana Prism. Though he doesn't want to wear a girl's costume, he is forced to be a magical girl as well! "Come back, my peaceful life!" To save his school, his battle against the magical girls starts now!