Kid Buu

The Kid Buu Saga is the last saga in the anime Dragon Ball Z. It deals with Kid Buu the final form of Majin Buu, who cannot be negotiated with, has no remorse, and no mercy. His sole reason for existence is to kill and to destroy. And he enjoys it. This version of Buu resembles nothing less than a small Evil Buu. East Kaiôshin (Supreme Kai) reveals that this is the original state of Majin Buu.
Kid Buu's first target is the Earth which in a psychotic episode typical of him he blows up the minute his transformation is complete. Vegeta, Goku, Hercule (Mr. Satan), Dende and the puppy Bee are the only survivors. Kid Buu tracks them to the otherworld and engages in one last climactic battle with Goku and Vegeta. But Goku and Vegeta aren't strong enough. Mr. Satan steps in and challenges Buu, but Buu finds himself unable to attack. Eventually he spits out something that turns into Good Buu. Mr. Satan overcomes his cowardice to fight for his unconscious friend. When Good Buu wakes up he saves Mr. Satan and then starts fighting Kid Buu. While this is going on Vegeta hits upon a plan. He has Dende, Supreme Kai and Rou Dai Kaiôshin (Elder Kai) travel to New Namek where they summon Porunga, the Namekian dragon. Vegeta has them wish for the restoration of Earth and the resurrection of everyone killed since the morning of the Tenka'ichi Budôkai(World Martial Arts Tournament), except for the most evil. The Dragon complies. Goku is amused to find Vegeta is resurrected, pointing out this means he is no longer evil. Vegeta then explains his plan, a Genki Dama(Spirit Bomb), made from the freely given energy of the people of Earth. He communicates to the entire planet via King Kai but only their friends and family believe him, the rest thinking it was all a dream. With the Good Buu now pounded into the dust Vegeta has to hold Kid Buu off so that the Spirit Bomb can be completed. Goku asks the people of Earth to help but only a few people Goku helped in the past give up their energy. As Vegeta hears this he gets more and more angry until he starts shouting at the people of Earth who hear him. Mr. Satan realises this and then proceeds to exhort them to give up their energy so that he can defeat Buu. He knows this is a lie and explains to Goku he doesn't believe they'd do it for anyone else. Thanks to Mr. Satan the Spirit Bomb is finished but Kid Buu has defeated Vegeta who is now too weak to move. Kid Buu knows Goku won't fire the Spirit Bomb because it would destroy his friend and so he stands on top of him while he continues to blast Goku.Out of nowhere comes the Good Buu who uses the last of his strength to knock Kid Buu over and pin him. He tells Mr. Satan to grab Vegeta. Kid Buu quickly recovers though and blasts the Good Buu but the way is now clear for Goku who fires the Spirit Bomb. But Goku is exhausted and Kid Buu is not only able to stop the Spirit Bomb, he is able to take control and fire it back at Goku. All seems lost until Vegeta asks Dende to make one last wish, to restore Goku's strength. With Goku renewed, he takes back control of the Spirit Bomb and directs it back at Buu. Buu tries to block it but it begins forcing him backward. For the first time his expression is one of fear, something he brought to so many.In the dubbed version of the anime, Goku says
"It looks like this is the end of the road Buu. It's a darn shame. When I first met you, you were like a naughty little child who didn't know any better. But the battle between good and evil that was taking place inside you took place on the outside, and the darkness overpowered the light. From then on you changed. You were ruthless. You were a living nightmare and you enjoyed every minute of it. And that's why it has to be this way. You've got to learn what it feels like to have your life taken away against your will. It's wrong. Maybe you'll come back one day as a better person i hope. We'll have ourselves a little one on one. I'd like that."With that he triggers the Spirit Bomb. Majin Buu is engulfed. His expression is a mixture of overwhelming terror and agony. With one drawn out scream his body disintegrates and he is gone. This was the end of Majin Buu, the villain who caused more death and destruction than any other opponent the Z fighters faced.Goku later wishes on the Dragonballs for the people to forget about Majin Buu to allow the Good Buu to walk around without being feared. And ten years later at the World Martial Arts Tournament the Z fighters meet a boy called Uubu. This boy is the reincarnation of Majin Buu. Goku agrees to train him, and they fly away. This also marked the end of Dragon Ball Z