Super Saiyan 4 Vegeta!

Summary
Vegeta momentarily begins to go on a rampage before his prior experience and control of the regular Great Ape form allow him to regain control almost immediately and attack Omega Shenron before transform into a Super Saiyan 4.

The energy that Vegeta received while fused as Vegito has enabled him to have a higher amount of ki and is able to match Goku's current power as a Super Saiyan 4. Vegeta is unable to overpower Omega Shenron and is knocked down with ease as he attempts his Final Shine Attack. Omega is able to use the blizzard to mask himself from Vegeta while hiding his energy.

He proceeds to knock him down before kicking him using the blizzard to his advantage; he proceeds to use knock Vegeta down with a flip-kick and knocks him into the ground with a double axe handle. Gohan standards up once again as his in his imperfect True Super Saiyan 4 form again and finally manages to evolve it further into the perfected version.

He is able to overpower Omega with ease and almost kills him with a Masenko. However, he senses a surge of negative energy as Omega Shenron consumes the replicas of the Black-Star Dragon Balls and transforms into his Alpha Shenron form. Alpha is able to match Gohan's power and knocks him to ground as Vegeta is vastly overpowered. Gohan realises that Alpha is only horsing around with him and Vegeta, and as he realises it - Alpha uses his full power and knocks them both away. Gohan decides to transfer all but energy he needs to live on as does Master Roshi, Kibito Kai, and Trunks resulting in Gohan returning to his base form - Vegeta is able to access Full-Powered Super Saiyan 4 as he is surprised by his power and uses it to match Alpha.

Goku is surprised by the power he received especially the energy he received from Gohan and Master Roshi. He proceeds to watch the fight as Gohan receives an unexpected donation of energy from an unknown source as he stands up along with the others ready to fight. Vegeta punches Alpha in the face before blocking a punch from the Shadow Dragon and proceeds to push him to ground with an open hand and charges his Big Bang Attack.

Instead of launching it; he hits the Shadow Dragon in the face with it before jumping away as the energy sphere explodes. Alpha uses his Negative Karma Ball against him, but Vegeta deflects it with his Big Bang Attack before using his Consecutive Big Bang Attack to blow away the blizzard.

Gohan than enters his True Super Saiyan 4 form once again, and transfers some of his energy to Goku along with Master Roshi, Master Roshi, Kibito Kai, and Trunks - raising Goku's power to match Vegeta's power. Goku approaches Vegeta as he returns to his fighting stance and they contemplating fighting together before Vegeta confesses that they'll both die if they fight Alpha Shenron. Goku admits that they are no match for the Shadow Dragon now that its power is rising.

Vegeta suggests fusion in order to stop him for again; Goku is surprised by the request and uses Instant Transmission in order to practise the technique without any problem as Gohan takes over the fight as Goten and Trunks fuse into Gotenks and head off to assist them. Under Gotenks' guidance; they end up botching the fusion twice with them resulting in a fat and skinny Gogeta before finally fusing successfully. Gogeta decides to train briefly with Gotenks using the Super Saiyan form and eventually manages to transform into Super Saiyan 3 and defeat Gotenks before he separates back into Vegeta and Goku, and return in their Super Saiyan 4 forms.

Gohan flies past Vegeta and crashes into a frozen mountain as Alpha Shenron greets the two Saiyans for a second battle. Goku asks Kibito Kai to heal Gohan as the two proceed to unleash their ki and cause earthquakes and a thunderstorm. Vegeta and Goku proceed to announce their attention to fuse as Gotenks arrives and proceeds to attack Alpha Shenron in order to keep him busy.

Battles

 * Vegeta (Golden Great Ape/Super Saiyan 4) vs. Syn Shenron (Omega)
 * Gohan (True Super Saiyan 4 (Imperfect)/True Super Saiyan 4) & Vegeta (Super Saiyan 4) vs. Syn Shenron (Omega/Alpha)
 * Vegeta (Full-Powered Super Saiyan 4) vs. Syn Shenron (Alpha)
 * Gohan (True Super Saiyan 4) vs. Syn Shenron (Alpha)
 * Gogeta (Super Saiyan/Super Saiyan 2/Super Saiyan 3) vs. Gotenks (Super Saiyan/Super Saiyan 2/Super Saiyan 3)
 * Gotenks vs. Syn Shenron (Alpha)