Vegeta allows himself to be brainwashed by Babidi and becomes Majin Vegeta. He then has his ultimate battle with Goku. After a long fight, Goku defeats Vegeta.
If the player defeats Vegeta before the transformation button appears on screen then Dabura will appear. Goku will then kill Dabura and go on to fight Majin Buu. Also, if the player loses to Vegeta at any point, Vegeta will knock out Goku, and head off to fight Majin Buu.