3x36 - Dragon Ball Z: Dragon Box

The mysterious young man defeats Freeza's men in quick succession. As Freeza and his father maintain their composure, he declares that "Son Goku-san is not the one and only Super Saiyan," and then himself turns Super Saiyan. Upon seeing him, Freeza recalls Goku, and giving in to his anger, attacks with an energy blast ten times greater than the one that destroyed Planet Namek...