Evil Kid Buu was the creation of Bipidi.
Buu's evil was so great that even Bipidi could barely sustain it. Buu set out, as his master commanded,
to destroy all the planets, that is, until he reached the Kai planet, where he was confronted by the Kais. Buu absorbed all
of them but one, and thus became lovable fat buu.
When Fat Buu was released from Super Buu's mind, he became Kid Buu. Kid Buu was finally destroyed by Goku
with a Spirit Bomb.