Zamasu manages to get the Super Dragon Balls, and summon Super Shenron. Making the wish to switch with Son Goku's body. This wish is granted, and Zamasu begins his Zero Mortal Plan... However, that is quickly interrupted upon realizing that this Goku has a heart virus. He heads off to get the Super Dragon Balls again to get the right body

Goku Black: "Last time, I called upon you for the ultimate body. One that could embody my divine justice. And get... You cursed me with a body afflicted by a mortal disease?! A heart virus?!?!"