More than likely, nothing. Chopper developed the rumble balls for his particular devil fruit and his own physiology. if anything, it might make Luffy sick, like food poisoning, but nothing like what Chopper can do with it.
Chopper was shifting through different transformations, before he reverted back to his little reindeer form, Viper stopped the timer and said "5 minutes and 24 seconds, that's quite the improvement," he frowned and said "But it would be better for longer... By the way Chopper have you ever tried with other devil fruits other than Zoan?" Chopper shook his head and said "I didn't have any other subjects" Viper said "Maybe we should try it on Luffy..." Chopper said "It could kill him!" Viper sighed and said "I really wish we had more test subjects..." before sulking back to the lab mumbling about capturing a paramecia user later, making Chopper shiver and following him.
One Piece: Another Chance (Completed)
Anime & Comics · Monkey_Godking
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