Emergency Escape from Inside the Body! Buu's Reverse-Transformation is the Worst!!
Having successfully severed the absorbed fighters from within, the Saiyans make a hasty retreat as Majin Buu's body begins a violent and unpredictable destabilization. Rather than weakening, the loss of his captives triggers a terrifying regression into the creature's original, uninhibited state. Unburdened by any remaining trace of reason, this primal force unleashes immediate, catastrophic destruction upon the world.
Aired 19/04/2015EP 51 - Emergency Escape from Inside the Body! Buu's Reverse-Transformation is the Worst!!
Dragon Ball Z Kai: The Final Chapters
Since Cell's defeat Gohan has grown up and go to the university then she meets Videl which who has some adventures, then both and his new brother Goten are training for the new tournament, in which Goku came back from the dead for one day. In half of the tournament a misterious persons advice the group about the resurrection of the dangerous Majin Boo, but all plans fails and every one try new ways to stop The dangerous Majin Boo who gets stronger each time. Goku and his friends make everything for stopping them through fights.
(Source: Anime News Network, edited)
Note: Remastered version of the Majin Boo arc that adheres more to the manga's story.