The Destructive Majin is one of the five what-if saga in the video game Dragon Ball Z: Budokai Tenkaichi. The protagonist of the saga is Majin Buu, and it revolves around him fighting the Z Fighters and create destruction around the world. This saga is unlocked after beating "The True Ultimate Android" saga.
Majin Buu is revived by Babidi and kills Vegeta. He then takes on Super Saiyan 3 Goku and defeats him using his true power. He later becomes Super Buu and defeats Super Saiyan 3 Gotenks. Goku and Vegeta then return to Earth and become Super Vegito but even that is hopeless when Buu self-destructs, killing them and going on to destroy all life on Earth.
Janemba then comes to Earth and Buu (now Fat Buu again) defeats him using his full power.
Having destroyed every last living person on Earth, Majin Buu was delighted with himself. Until a certain realization of loneliness came over him... And now the screams of Majin Buu are all that echo over this land. And there is no one to hear them.