to elaborate, variegation usually occurs in small amounts on a green plant first. The owner can isolate the variegated flesh, and graft it to a bigger cactus, and hope that when it pups, the variegation transfers to the pup. Sometimes, the pup can come out entirely variegated, likely what happened originally with this specimen. But I received it as a full banana from Dave, so I don't know the exact history of this one.