In their debut film, the clan turns their attention to Earth. They land their spacecraft on Earth and terra-freeze Earth's atmosphere, planning on turning the planet into a Planet Cruiser to use as transportation.
Slug later reads the mind of Bulma and learns about the Dragon Balls. He steals the Dragon Radar from her and gives it to his henchmen before sending them to go collect the Dragon Balls. After receiving the balls, he uses them to restore his youth and health.
Gohan later attacks Slug's army but soon becomes outnumbered. However, he is soon saved by Piccolo. Piccolo and Gohan face Slug's top three henchmen: Angila, Wings and Medamatcha. Piccolo fights and kills Wings, while Gohan battles Medamatcha and is quickly overwhelmed. Luckily, Goku shows up and defeats Angila and Medamatcha.
Lord Slug then appears and fights Goku before using his powers as a Super Namek to grow giant. Gohan then starts whistling which, because the wavelength causes it sound terrible to Namekians, brings Lord Slug down, allowing Goku to punch a hole through him and finish him off with a Spirit Bomb.