The shield cutie mark. Every Crusader, even Gabby, has one now, so everypony who doesn't have one isn't a Crusader. That's what Babs' uncle has been telling her ever since the incident. That's what she's come to believe.

But could it really be true?

Image made from canon and grayscaled by me for the feels to make it more dramatic. May contain slight headcanon about Babs' past.