Boku wo Sodatete! Nyanda Seijin (2018)

A free raising simulator about raising an alien boy.

Storyline

My husband divorced me because I couldn't have children. One day, I found a strange egg. I didn't know what kind of egg it was, but since I'd been wanting a pet, I decided to take it home and try raising it. Surely a cute little bird would hatch... But to my surprise, what hatched from the egg was a tiny boy with cat ears!? This child, who called himself a "Nyanderian", asked me to raise him for five days until he became an adult...