"Wh—" Before Yang can ask what the hell, the dude in the (kind of goofy but also kind of badass looking) costume is up next to her she feels the sensation of having her ears scratched. It's an entirely new, and alien feeling, but one she instinctively realizes is "oh, my ears are getting scratched and this feels kind of nice actually, I see why my dog is such a fan"

The next thing she does is to pull back with her non-metal arm (she doesn't load it with a shotgun shell from Ember Celica, but oh god the temptation is there because seriously, what the HELL and punches the guy right in the gut.

She can address the furry thing once she's made her objection clear.