So, some time ago (long enough ago that I forgot about it), an artist named PajamaHam asked for people to request free art of their MLP OCs. On a lark, I threw in A-Okay because, well, I forgot the reason.
For those wondering, A-Okay is a unicorn mare who's special talent is basically being able to survive and regenerate from the kinds of damage what would kill most ponies. If you remember what Twilight Sparkle went through in Feeling Pinkie Keen, you can take that up to R-rated levels for what A-Okay can regularly go through. This tends to frighten other ponies.
And I gotta say, doing your own stitches has got to be painful, thus her seemingly angry look. She's normally much calmer and softer in personality.
She may or may not be a zombie pony, but if she is, she's certainly not the flesh/brain eating type. (though, Grrraaaiiinnnsss, maybe. Or it could just be that you need all those nutrients to recover from all those constant injuries.)