Animate Prosthetic

You imbue one willing creature with the ability to control a magically crafted prosthetic. The ritual time takes 24 hours and must be completed without breaks. Upon completion of the ritual spell, the caster rolls 1d20 to determine the effect of the spell casting:

10-20: The prosthetic works as designed, fully replacing and even enhancing the wielder’s natural motor function with that body part.

5-9: The prosthetic works mostly as intended, but infrequently malfunctions, causing spasms and pain throughout the wielder’s body.

2-4: The spell fails and the metal is consumed harmlessly.

1: The spell fails catastrophically, dealing 4d10 necrotic damage to the intended wielder and half as much to the caster.