Dragon Ball Super: Season 4, Episode 18

4 - 18: Praise and Adore Him! The Explosive Birth of Merged Zamasu!!

Vegeta continues overpowering Goku Black, who deduced rage as a factor in Saiyan's power increasing and uses the method to increase his strength enough to cut a rift in space. Black proceeds to keep Goku and Vegeta at bay with his energy duplicates of himself while Zamasu goes after Future Trunks, Future Mai, and Bulma as they attempt to repair the Time Machine. Giving Future Trunks and Mai a video of Piccolo teaching her the Evil Containment Wave, Bulma attempts to buy them time by flirting with Future Zamasu and nearly gets herself killed. Luckily, Trunks arrives and uses the Evil Containment Wave to trap Zamasu in the jar. But Goku forget to bring the charm needed to stabilize the seal with a traumatized and weaken Zamasu breaking free as everyone regroups. Realizing that they can no longer underestimate their enemies, Goku Black and Future Zamasu use their Potara earrings to fuse into an immensely powerful being.