Death Ball is Frieza's most powerful technique. He holds his finger pointed upwards, and a massive sphere of energy grows from the tip; when thrown, it destroys everything in its path, including planets. Frieza used the technique to destroy Planet Vegeta and Planet Namek, and attempted to use it to destroy Earth. In the feature movie "Cooler's Revenge", Cooler used a form of it, otherwise known as the Supernova, in order to kill Goku and destroy the Earth at the same time.
Cooler also used this technique.