Kaibutsu-kun (1980)
Original title: 怪物くん
Kaibutsu-kun is a 1980 Japanese-language animation series created by Fujiko A. Fujio. It stars Masako Nozawa, Katsue Miwa and Chiyoko Kawashima.
As part of his training to succeed the throne, he visits the human world, where he has various adventures with other monsters.