Puniru is a Kawaii Slime Season 2

Kotarou Kawaii is a second-year middle school student who's had a unique friend for the past seven years. This friend, a slime named Puniru, came to life when Kotarou was in elementary school, and he's been spending time with her ever since. However, with both of them growing up, Puniru has developed a more feminine appearance, and Kotarou is now facing the challenges of navigating their relationship in a way that's different from their past as "just friends.