La Fin du tyran

Frieza fires a second energy disc, and the pair will follow Goku until they hit him or anything else. Even so, Goku has the situation under control as the battle draws to a close end. Eventually, Frieza is cut in half by his own energy disk from behind. Frieza begs for mercy, and Goku, being the kind person he is, gives him some of his power to live and escape the planet's destruction. (Source: Wikipedia)