"Make countless powerful Ki Waves rain down from midair!"
Super Buu raises his hand up in the air and charges a pink aura around his body. Then, he fires a massive barrage of pink energy waves up into the air to rain down on the opponent, inflicting a large amount of damage.
Super Buu uses this attack to kill all of the human beings on Earth. When Piccolo suggests to an impatient Super Buu that Buu could kill some humans while waiting to fight Gotenks (conditionally promising to his friends that he will wish the victims back to life), Super Buu walks around Kami's Lookout to calculate the number of humans still alive and then proceeds to use the attack to lethal effect, killing everyone on the planet in a matter of minutes. Only Tien Shinhan and Chiaotzu are skilled enough to dodge the blasts and escape from death. Mr. Satan and Bee are also spared due to the friendly Good Buu's influence on Super Buu.
Fused Zamasu used a similar technique in the manga on Goku and Vegeta in their fight, to show off his power. Goku and Vegeta managed to evade most of them and Goku blocked all energy blasts heading towards Shin, Gowasu, Future Trunks, and Future Mai.
Appearances in games
This technique was named Energy Shower in the Butōden series, Annihilation Attack in Dragon Ball Z: The Legend, Human Extinction Attack in Dragon Ball Z: Taiketsu, and Genocide Attack in Dragon Ball Z: Supersonic Warriors.
It appears as one of Super Buu's Blast 2 attacks in the Budokai Tenkaichi series; it was first named Extermination of Mankind Blasts in Dragon Ball Z: Budokai Tenkaichi, but was later named Genocide Blast in Dragon Ball Z: Budokai Tenkaichi 2, Budokai Tenkaichi 3, Tenkaichi Tag Team, and the Raging Blast games.
It is named Assault Rain (アサルトレイン) in Dragon Ball Heroes, as well as in Dragon Ball Z: Supersonic Warriors 2, Dragon Ball Z: Shin Budokai, Dragon Ball Z: Shin Budokai - Another Road, and Dragon Ball Z: Infinite World where the technique can be used by Kid Buu. Kid Buu also uses the technique in the opening movies for Dragon Ball GT: Final Bout and Dragon Ball Z: Budokai Tenkaichi. In Dragon Ball Online, the Human Extinction Attack is one of the techniques used by the Majin race.
In Dragon Ball Xenoverse, it appears under the name Assault Rain (アサルトレイン) and is Super Buu's Ultimate Skill. It can also be obtained by the Future Warrior as a reward in Parallel Quest 37: "Potara Warrior". Unlike Dragon Ball Online it can be used by members of any race (Human, Saiyan, Namekian, Frieza's race, and Majin). It is also used by Super Buu as a Super Attack in Dragon Ball Z: Dokkan Battle.
In Dragon Ball Xenoverse 2, Assault Rain returns as one of Super Buu's Ultimate Skills which can also be obtained by the Future Warrior (Xenoverse 2) as a reward in Expert Mission 09: "The Most Feared Majin".
In Dragon Ball Fusions, two weaker variations of Assault Rain are introduced. The first is Shooting Rain which is the weakest and the second is Shooting Bullet which is stronger than Shooting Rain but weaker than Assault Rain. Assault Rain itself is depicted as the strongest of the three. If Tekka is selected as Offworlder, then they can learn Shooting Rain and then Shooting Bullet once they reach a certain level. Mirayo can learn Assault Rain at Lv. 64. Offworlder Tekka can also learn Assault Rain after reaching Lv. 80.
- Shooting Rain - A weaker variation of Assault Rain that appears in Dragon Ball Fusions.
- Future Android 18 uses a similar attack in the TV special Dragon Ball Z: The History of Trunks, against the hiding Future Gohan and Future Trunks.
- King Piccolo uses a similar attack as well, in the video game Dragon Ball: Revenge of King Piccolo. Once he finishes, he uses an Explosive Wave.
- It is by far the most lethal Energy Barrage technique ever used in the series due to it wiping out most of the Earth's population with extreme precision.