Buu is a very powerful, but kinda bratty Majin (devil aliens who want
to destroy the Earth for no reason)
who was summond by Dabura but he couldn't be released until he had
powerful enough minions
. When Vegeta became one of his minions he had enough power to be released.
He has the ability to absorb people
by turning them into candy
After being released Buu makes an evil twin of himself who absorbs
him and the evil Buu then becomes Super Buu.
Once the good Buu inside him denies fighting Mr. Satan he spits out
good Buu and tears Mr. Satan up
but he also is not Super Buu he is Majin Buu.Then Magin Buu fights
Super Saiy-jin level 3 Goku and
beats him. He fights Gotenks and absorbs him becoming Majin Gotenks
Buu. Then he also absorbs many others
after that. To saved the absorbed Z fighters Vegetto gets absorbed.
Then Buu destroys Earth and kills almost every
one. Then he is defeated by Goku's Spirit Bomb and the Earth is restored
with the Namek Dragonballs.