WotC just shared this Arcane Propulsion Arm! It functions as a 1d8-dmaage magic melee weapon which you can throw (don't worry, it flies back and reattaches).
Using lingering injuries from the DMG. Or alternatively, plot and or character concept reasons.I think it raises interesting questions about what magical healing - like cure light wounds - actually DOES. Mechanically, a character cannot lose a limb in D&D (except maybe to a vorpal weapon or similar). But if we allow that dismemeberment can happen, would we allow a cure wounds spell - perhaps of high enough level - to restore a lost limb? Do we need regeneration for that?
Under what circumstances would a character actually end up with a use for this item?
No. It specially states it is a magic melee weapon (so you could cast GFB etc. with it), something is either a weapon or unarmed, not both.The real question though:
Would you let it count as an Unarmed Strike?
I suppose. I'd actually forgotten about the lingering injuries option, to be honest.Using lingering injuries from the DMG. Or alternatively, plot and or character concept reasons.
And even within Eberron, it would be an interesting choice to deny magical healing for the chance at a prosthetic. I mean, characters do what characters do, but it seems an odd thing to desire given the other options generally available.
Prepare for Trouble!