This is assuming Cell in the afterlife destoryed King Kai's planet before going to judgement because Cell is a vengeful prick.And there are some differences here.Full Power Bojack=Super Perfect Cell in this.AND Vegeta mastered the Super Saiyan transformation. And Trunks taught himself Galick Gun.

ChiChi said,"Goku,you know what I said." Goku said,"I won't intervene." (When Bojack Arrives) Gohan said,"Let's get this started." And elbowed Bujin.He then flew up.He dodged attacks from Zangya and Bido.Future Trunks killed Kogu.After an beating,Gohan saw Bojack fire a Full Power Energy Ball."Special Beam Cannon...Fire!" A familiar blast deflected the ball of power into Bido,killing him."Grand Smasher." Piccolo fell to the ground.Bojack charged one more attack until Future Trunks repeatedly blasted him but Bojack activated Psycho Barrier,but the blasts then landed on Bujin,allowing him to meet his end.Bojack then blasted Future Trunks. "BOJACK!!!" Vegeta went Mastered Super Saiyan."HAAAAAAAAAAAA!" Vegeta fired a strong energy blast.Bojack went Full Power and easily withstood said blast.Vegeta fired many blasts.Full Power Bojack slapped MSSJ Vegeta away."Goku,now you can intervene!" ChiChi yelled."Right!" Goku used Instant Transmission and went MSSJ.He gave Vegeta a Senzu Bean.Vegeta went MSSJ."Alright Kakarot.Got a plan?" Vegeta asked,ready for a fight. "Honestly,yeah." Goku continues,"Hit him with our strongest blasts.You ready?" Vegeta jumps up and yells,"I was born ready! FINAL......FLASH!" Goku jumped up and yelled,"Good! KA....MEEEE....HAAAAAA......MEEEEEEEEEE..........HAAAAAAAAAAAA!" Full Power Bojack smirked."Grand Smasher." The pale green blast collided with a blue and yellow blast.The pale green blast easily overpowered the mixed blast. (Boom) Gohan saw his father be defeated."GRRRRRRRR.......AAAAAAAAAAGGGGHHHHH!" Gohan went Super Saiyan Two after a mighty yell of power and the island shook."GALACTIC BUSTER!" "KA......MEEEEEEE.......HAAAAAAAAAA......MEEEEEEEEEE......HAAAAAAAAAAAAAAAAAA!"                               The blasts seemed perfectly equal. Goku got up and killed Zangya.He gave Yamcha,Tien,Krillin,Vegeta,Future Trunks,Piccolo,and himself all Senzu Beans. "My son needs our help!" The Z-Fighters agreed with Goku,even Vegeta."SUPER....KA...MEE....HAAAAAA.....MEEEEEEEE.......HAAAAAAAAA!" "FINAL........FLASH!" "SPECIAL BEAM CANNON!" "GALICK GUN......FIRE!" "DESTRUCTO...DISC!" "NEO TRI-BEAM...HA!""SPIRIT BALL!" Gohan's Kamehameha overpowered Bojack's Galactic Buster.Bojack slowly disintegrated.