Dragon Ball Z is filled with fearsome foes, but few can compare to Majin Buu's ancient evil. Majin Buu is the last major villain that's faced in Dragon Ball Z and, in many ways, this antagonist feels like the culmination of the series' previous threats. Majin Buu cycles through various transformations like Evil Buu, Super Buu, and Kid Buu. However, Buu also experiences several absorption-based upgrades that reward him with all of his victims' powers.
Source：https://www.cbr.com/dragon-ball-underused-majin-buu-powers/
