The Old Kai's Weapon (全宇宙のために...よみがえれ孫悟空, Zenuchū no Tame ni... Yomigaere Son Goku) is the thirteenth episode of the Fusion Saga and the two hundred sixty-sixth overall episode in the original dubbed and the uncut Dragon Ball Z series. The episode first aired on May 31, 1995. Its original American air date was November 5, 2002.
Newly transformed, Super Buu is on the attack now having absorbed SS3 Gotenks and Piccolo. Gohan, bruised and tired goes on with the fight. Goku and the rest of the people on the Sacred World of the Kais watch on through a Crystal Ball. The battle on Earth really starts to heat up when Super Buu fires a Special Beam Cannon which Gohan blocks but at the expense of what little energy he has left, and Super Buu then follows it up by a Super Ghost Kamikaze Attack. They both hit Gohan and really drain what is left of his power. Moving in for the kill as Super Buu grasps Gohan in his hand and powering the other hand up to deliver the final blow, Mr. Satan's dog, Bee, decides to bark at Super Buu.
Back with Goku and the Old Kai, the Old Kai gets an idea. He decides to give his life for Goku's so Goku may return to Earth to fight while King Yemma and Fortuneteller Baba decide to bring back the Saiyan Prince Vegeta.
Gohan finally loses every bit of energy he has and just gives up as Bee gets closer to Super Buu. Aiming his hand towards Bee now, Mr. Satan kicks Super Buu in the head 3 times and falls to the floor. Super Buu is about to fire the blast but Gohan awakens and kicks Super Buu stopping him from killing Bee and Mr. Satan. Super Buu quickly recovers and fires Galactic Donuts at Gohan and wraps him up. Super Buu wants to finish this and starts to power up a Kamehameha. Right after unleashing it Gohan breaks free of the bindings and dodges the attack.
The Old Kai sits down and begins to bid farewell as he dies and falls to floor. Goku's halo disappears and becomes alive again as he is about to leave. The Old Kai sits up and yells at Goku to leave already as he now has a halo over his head.
Gohan, now is fleeing for his life as Super Buu continues to hunt him down. Old Kai has yet another plan. He tells Goku that he still has no chance. Goku thinks that fusing with Gohan might work, but Old Kai explains to him they have no time to practice the Fusion Dance, so he takes off his Potara earrings, hands them to Goku telling him that if they put them on, they will instantly join bodies and become one person. Shin and Kibito, having not been told the effects of the fusion are permanent, accidentally fuse into Kibito Kai.
- Ultimate Gohan vs. Super Buu (Super Saiyan 3 Gotenks and Piccolo absorbed)
"I possess the greatest powers in the universe! And I'll use them all to kill you!"
"Hardly recognized you, Gohan. You've changed a lot, inside and out. Good for you. But I see Majin Buu did some changing, too."
- Special Beam Cannon - An energy wave that can drill through nearly everything and every being. Used by Super Buu against Gohan, but the Saiyan manages to block it.
- Mystic Attack - A technique where the user has the ability to stretch his arms or legs. Used by Super Buu to smash Gohan through nearby rocks.
- Super Ghost Kamikaze Attack - The user spits out a small ghost that creates a huge explosion upon contact with anything. Used by Super Buu against Gohan to full effect.
- Spread Shot Retreat - An evasive technique where the user fires ki blasts while moving backwards. Used by Gohan to escape from Super Buu Super Ghost Kamikaze Attack.
- Galactic Donut - A ring of energy that traps the opponent. Used by Super Buu against Gohan, leaving the Saiyan helpless.
- Super Kamehameha - A more powerful version of the Kamehameha. Used by Super Buu against a trapped Gohan, but the Saiyan manages to escape the Galactic Donut and dodge the blast in time.
- Super Buu says "That really hurt, didn't it Gohan? Facing your fears would have been less painful." This is what Piccolo (who at this time is absorbed) said to Gohan after he "froze" when he was supposed to attack Nappa during the Saiyan Saga, which was set eleven years, fifteen sagas, and 252 episodes ago (going by the first English 276-episode version).
- When Mr. Satan is about to attack Super Buu, his mustache is missing its black color for a moment.
- This is the second time Goku is brought back to life. When this episode aired on TV, however, its introduction theme was not changed like it was in the episode "The Return of Goku".
- In the remastered version, when Super Buu says to Gohan "That could've been your head", the "That" was removed for some reason, making the quote sound like "Could've been your head."
- This episode marks the return of Vegeta in this episode. He was previously disintigrated after using his Final Explosion to destroy Buu in "Evil Lives On".