There’s a Star Wars comic book that came out recently chronicling the adventure C3P0 went through to end up with that red arm he’s sporting in Force Awakens.
Although I have yet to read the comic, I’m pretty sure the story has nothing to do with him riding around on a My Little Pony, but I drew this image for my friend Reagan (age 4 and a half) to color as she’s a big fan of both properties.