First, put the skill level on hard. Get Super Saiya-Jin Goku Level 4 and the rest of the hidden characters. This includes Gotenks. Note -- You cannot lose a match and you need near perfect when getting all the hidden characters. Once done, beat the game on hard 7 times with Majin Buu a.k.a. Original Buu. You need a near perfect doing this and no losses. After that's done, beat the game 15 times on hard with Pan. You also need a near perfect and no losses here too. Beat the game 6 more times with Chibi Goku with a near perfect and no losses. 8 more times with SSJ to the 4th power Goku. You also need no losses and near perfect every match here too. Finally beat the game 3 times on easy with Majin Buu. On the third time you need to continue 4 times by losing to your first round opponent. And get a perfect on every one after that. Except for when you fight Super Baby. You need to half your life bar at 1/4 the way, and finish Super Baby with a strong 'Ki Attack' (or in other words ---- a strong knockout ki blast.' i.e. Goku's "Chou Kamehameha," but for Buu! After that, go to the character selection screen and highlight Majin Buu. When you do that, press the select button 15 times and Ubuu will appear.