what do you think would happen if another devil fruit user used the rumble ball like luffy,robin,brook or do you think it would only work for zoan type users and if it did work on other devil fruit users what do you think would happen?
Well We have seen it work for chopper who is a Zone type may be it will work for the other Zone Type User like In the CP9 Commenter who fought luffy Or it may not workwhat do you think would happen if another devil fruit user used the rumble ball like luffy,robin,brook or do you think it would only work for zoan type users and if it did work on other devil fruit users what do you think would happen?
-.-Chopper was the developer/creator of the rumble ball. The rumble ball only works on Zone-type devil fruit users. If another Zone-type devil fruit user were to consume the rumble ball, it would result the same as it did for Chopper. It would give them three additional transformations which can be used for three minutes. There is more to it that what I said since Chopper only needed one rumble ball for one transformation after the timeskip - it might be only him though.