Except to say this: she said something to Heidi today that alluded to the idea that she thinks no one in the store likes her. The irony is, if she just treated us politely and professionally, she wouldn't have to worry about it. Instead, she bitches about us to our supervisors - which gets back to us - and then acts fake-nice to us when she's with us in person.
But I'm not making great choices about her, either, as long as I keep talking about her. I've decided to stop spreading toxicity, and just be done with her. She doesn't deserve any more than that.