Dragon Ball Z Movie 04: Super Saiyajin da Son Gokuu

A massive object appears on a collision course with Earth. Goku and Krillin fail to stop it, only for the object to reveal itself as the vessel of Lord Slug, a ruthless Namekian conqueror who quickly begins transforming the planet for his own use.

Slug steals the Dragon Balls and restores his youth, becoming even more dangerous as his army overwhelms Earth's defenders. Goku eventually learns that Slug is a powerful Super Namekian, and defeating him requires help from Piccolo, Gohan, and an unexpected weakness in Namekian senses before Earth is stripped of life.