If/when you saw Star Wars: The Force Awakens, you likely cocked your head a bit when C-3PO appeared on screen sporting a red arm and thought, “Huh, that’s new.” C-3PO’s been through a whole lotta space war, so, when it wasn’t explained in the film, you probably left the theater wondering, but just chalked it up to space war is hell. Well, now you can learn the (pretty radical) backstory.