That looks like Harley, except she's acting different and is striking poses. Ben would have blinked if he still had eyes.

"Nega-what? I don't even know what that means." Ben's genuinely surprised, and the horse rears up in shock when Sailor Quinn appears. He puts his hands up. "Harley, it's me, Ben! Wait...so this spell got to you, too. This isn't going to work, is it?"