Kaibutsu-kun the Movie

Kaibutsukun is the young prince of Kaibutsu (monster) land who decides to go to Earth to prove to his people that he is worthy of becoming king. Kaibutsukun is accompanied by his friends Dracula, Wolfman, and Franken. The Prince decides to go to Japan to visit his friends Utako and Hiroshi. The Prince, Dracula, Wolfman and Franken are in for a surprise...
(Source: AsianWiki)
~~ Adapted from the manga "The Monster Kid" (怪物くん) by the writing duo Fujiko Fujio (藤子 不二雄).