Goku black arc

Zamasu has merged with goku black and has been now corrupted at Goku's attempt to destroy him with the hakai technique

Goku: "Vegeta, we have to fuse, it's the only way we can win!

Vegeta: "Like i will fuse with the likes of-! okay let's do it."

They fuse into VEGITO and go to face corrupted merged zamasu

Vegito: "And here's something new... Vegito.. BLUEEEEEE"

VEGITO goes super Saiyan blue but right at that moment he becomes a cat.