Two sisters! Proxy is mine, Exo is Fimp's. They're both Vulpes cthonae, a fox-based species made by  mythril-blackpaw with some interesting customs regarding prostheses. They all have at least one; it's a coming-of-age thing or something. Proxy's is a bunch of metal brackets all around hir body that allow parts to be detached; they can be reattached to any other bracket of the same size, with any rotation allowed by the flanges all around. Exo I think has a mechanical digestive tract or something; I just know fimp designed hir around vore! Both of 'em are indestructable too :D

Art by  fimp
Species by and commissioned(?) by  mythril-blackpaw