Physical attack. Your opponent draws 5 cards. If successful and you did not declare a Tokui-Waza, you win the game.
Errata:
If your opponent uses Where There’s Life, There’s Hope (Trunks Saga #157), you win when its effects end. If King Kai’s New Home (#R12) is in play when Cosmic Backlash is used, the opponent is allowed draw cards above the limit stated on the card.