Title: Dragon Ball Z Movie 13: Ryuuken Bakuhatsu!! Gokuu ga Yaraneba Dare ga Yaru
English title: Dragon Ball Z: Wrath of the Dragon

The Z Warriors discover an unopenable music box and are told to open it with the dragon balls. The contents turn out to be a warrior named Tapion who had sealed himself inside along with a monster called Hildegarn. Goku must now perfect a new technique to defeat the evil monster. 

(Source: ANN)