Magical Hat.

Magical Hat is an anime series by Studio Pierrot. The 33 episode series aired on Fuji Television from October 18, 1989 to July 6, 1990. The series stars Hat, the descendant of a hero who fought an evil king and sealed Devildom. Hat falls into Devildom and finds he has to defeat the evil king. The Sega Mega Drive game Magical Hat no Buttobi Tabo! Daibōken is based on this series; in Western regions the game uses different characters and is named Decap Attack.