Guru Guru Pon-chan volume 4 - Ikezawa, Satomi

But when Grandpa Koizumi, an amateur inventor, creates the Guru Guru Bone, Ponta discovers she can use it to turn into a human girl! Ponta quickly meets and falls in love with Mirai Iwaki. Plus Mirai's ex-girlfriend wants him back - by any means necessary. When Mirai and Ponta go to the beach together, the trip turns disastrous.