User blog comment:IamJakuhoRaikoben/Chapter 462: Battlefield, Review./@comment-5303512-20151117030621/@comment-7418318-20151117211217

Ah, I've been waiting for such an argument for two month or so :D

Regarding One Piece being original, you might want to check out Parasyte. Because there the main character has a hand that can stretch quite far (among other thing) which can easily be seen as giving "inspiration" for Luffy's gomu-gomu abilities.

And while the anime has come out only quite recently, the Kiseiju manga came out quite some time before One Piece.