It was a freak accident. Crazy freaky accident. It had happened so fast that you didn't even remember what had exactly happened, You just remembered suddenly feeling off balanced in the middle of a fight and the next thing you knew you woke up in medical with Chopper

Your arm had been sliced off. Cut through the bone right where your shoulder met your forearm

It was a bizarre thing to wake up to, even weirder to get used to it being gone, but luckily Franky had been more than enthusiastic to build you a Prosthetic! Maybe because that would mean another member with Robotic parts like him, or maybe it was just because he enjoyed building things like that

You grunted a little as the prods inside the cybernetic sleeve pricked into the still healing stump of your arm, but it was over as quickly as a Pinch. Franky leaned back with a wide frin as your muscle memory and brain worked to make the parts move, flexing the fingers and rolling the elbow

" Ta-da~! Not so bad if i say so myself! What do you think about it?" He asks chipperly, completely missing the slightly saddened look on your face as you moved the prosthetic around