Dragon Ball Z: The Return of Cooler

A few years prior, the tyrant Frieza destroyed the Planet Namek during his battle with the newly transformed Goku. The peaceful Namekians found themselves without a home for months. Eventually they had a new planet created for them with the help of the Dragon Balls. For three years or so they lived in peace on their new planet. One day however, a strange metal planet began to absorb New Namek. The silver planet wrapped around New Namek, absorbing its energy. Dende (Dragon Ball), who is now the Earth's guardian, senses the plight of his people and calls Goku for help.