Dragon Ball Kai - episode 48 - 13 Mar, 2010

The transformed Goku renews his battle with Frieza and proves now to be far superior to Frieza's power. Frieza launches several counterattacks at Goku, but they have no effect at all. As the tyrant stares in awe at his more-powerful opponent, he realizes that his worst nightmare has come true - a Super Saiyan, which Frieza had long secretly feared, has finally been born. In a desperate attempt to defeat Goku, Frieza hurls an attack down upon Namek itself, in an effort to destroy the planet and everyone on it. (Source: Wikipedia)