"The Ultimate Combination!!" (孫悟空最後の合体！！ Son Gokū Saigo no Gattai!!, lit. "Son Goku’s Final Fusion!!") is the three hundred ninth chapter of Dragon Ball Z and the five hundred third overall chapter of the Dragon Ball manga.
Having just absorbed Gohan and achieving even more power, Super Buu now threatens Goku to find a new person to fuse within under five seconds with the Potara earrings. As Goku begins to panic, he finds Dende and Mr. Satan. Goku begins to imagine the effects of using with both of them, realizing that if he fuses with Dende, the Dragon Balls will cease to exist and have no hope to restore the Earth. After much thought and hesitation, Goku reluctantly decides to fuse with Mr. Satan, yelling at him to catch this earring and put it on. However, before Goku throws the earring towards Mr. Satan, Goku notices a large power level nearby, and recognizes it as the deceased Vegeta's power level, sent back to Earth by Fortuneteller Baba and King Yemma to assist Goku. Greatly pleased, Goku uses Instant Transmission to teleport to Vegeta before Super Buu hits him. When Fortuneteller Baba leaves the scene, confused as to how Goku is alive again (Baba did not witness Old Kai giving his energy to Goku), Goku requests for Vegeta to fuse with him and form the ultimate warrior to combat Buu. Vegeta quickly refuses, feeling embarrassment for Goku hiding his true powers in their battle while Vegeta was a Majin, also explaining he witnessed Goku using Super Saiyan 3 while his soul was stuck in Hell after his failed attack on Innocent Buu. Deciding he would rather die, Vegeta continues to stare at Super Buu who is quickly rushing toward the Saiyans. Goku however, starts to become impatient and starts to yell at Vegeta, informing Vegeta that Buu has eaten everyone they know, including Vegeta's wife, Bulma, and has absorbed his son, Trunks. Vegeta, realizing and enraged that Buu killed his family, now orders Goku to quickly toss him the earring to fuse, making Goku smile. As Vegeta puts the earring on his right ear, Goku just then quickly informs Vegeta the fusion is permanent. While this information angers Vegeta further, he still puts the ring on his ear. As Goku thanks Vegeta for putting his family before his pride, the two fly towards each other, as a large blast of light bursts from their location. Super Buu, just preparing to fire an energy ball at the previously bickering Saiyans, stops his charge, and as the light dimmers, one new warrior is where Goku and Vegeta used to be and greets Super Buu, who is in complete confusion.