Luffy Should Create a Bucket or Better Yet a Hose!
If Luffy is soooo worried about the Five Elders supposedly being immortal or whatever...
Why doesn't he just make a giant bucket and fill it with sea water and throw it at them?
Better yet, why doesn't he make a giant hose and spray them down?
I mean, he could at least check to see if they're Devil Fruit users or not.
Even a sprinkler would do for God's sake