Ugh, some people don't have a clue how to be a decent human being. And if they don't even show interest in learning how to act or even co-exist with other human beings, they're not worth a single breath of ours. I'm glad your other friends are already aware she's a moron, so you should have no worries about her swaying someone in the direction she'd like.
There was a girl in junior high who was insanely jealous of me, although to this day I don't know why. She did what she could to bring me down to her level, and make me miserable, and unfortunately my "best" friend would sometimes find it funny to join her in humiliating me.
She made me cry more times than I can count. Since we've grown up, we relate to eachother in a much more mature way, but things will never,
never be cool between us, no matter how hospitable we are with eachother. It's awkward enough that I still see her sister around now and then. Although I always got along with her sister just fine, it brings back memories that aren't exactly pleasant for me.