The Reserved Transformation of Gotenks! Super Gotenks 3!!
Pushed to the absolute brink during the battle, Piccolo takes a drastic, irreversible gamble to ensure Majin Buu can never threaten the outside world again. Shocked by the dire situation, the fused warrior realizes he can no longer afford to play around. Cornered with no room for error, Gotenks decides it is finally time to reveal one ultimate ace up his sleeve.
Aired 25/01/2015EP 41 - The Reserved Transformation of Gotenks! Super Gotenks 3!!
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.