You Can't Escape from Mizudako-chan!

Synopsis

Kanisuke Akigai is just your average high school student, but when a demi-human girl named Yuuko Mizuda (nicknamed Mizudako-chan) transfers into his class, his life is turned upside down! She's cute, mysterious...and a little scary? The pressure is on as Kanisuke tries to understand his strange new classmate! (Source: Yen Press)