Dragon Ball Super: Season 4, Episode 20

4 - 20: One Last, Great Comeback! Here's Vegetto!

Goku puts everything into his Kamehameha to injure Merged Zamasu, injuring his arms before using his Kaio-ken technique to knock his opponent down when he grabs his foot. But Goku collapse while Merged Zamasu begin to improperly heal, Gowasu assuming that Black's mortal body is disrupting Zamasu's indestructible body. Goku decides that the only way they can win is for him and Vegeta to fuse using Shin's Potara earrings, Vegeta reluctantly agreeing after Gowasu explains that a Potara fusion that does not involve a Supreme Kai only lasts for one hour. The newly fused Vegito powers up to Super Saiyan Blue, who dubs himself "Vegito Blue", and battles Merged Zamasu who eventually turns the table after admitting that becoming half-mortal was intended to remain true to his goals as Gowasu considers his apprentice becoming an embodiment of everything he hates. Meanwhile, after the survivors regroup with Bulma and Future Mai as they finish repair the Time Machine. Future Mai gives Future Trunks his broken sword, which inspires him to keep fighting as he channels his energy through it. Future Trunks arrives in time as Vegito's fusion abruptly ends as the result of his immense power. Future Trunks unknowingly begins gathering energy from all living things on Earth and creates a Spirit Bomb, which he channels into his sword as he runs through Merged Zamasu and cuts him in half.