I'll Beat You in 5 Seconds! (5秒で倒す！) is a technique in Dragon Ball Z: Budokai Tenkaichi 3. It is used by Goku in his Super Saiyan 4 form. Goku raises his fist and announces "I'll Beat You in 5 Seconds!" while a red aura swirls around him. Using this attack powers up Goku's melee and Blast 2 attacks severely, but apparently only for five seconds, hence the name (not counting cinematic moves and events).
This technique is based on Goku's comment when fighting Eis Shenron, claiming that he will beat the Shadow Dragon in five seconds, when the latter prepares to freeze the entire city they are battling in.