Given the opportunity and the motivation, Vegeta takes Babidi up on his offer and becomes Majin Vegeta. This is solely for the purpose of fighting Goku ... apex in the fight with Buu, Vegeta ...

This development boosted the heroes' strength, allowing them to fight ... Goku about his Super Saiyan 4 transformation. Goku confirmed that he unlocked the new form after fighting Majin Buu.