What should I do about this chick?

We met a year and a half ago. We never talked much, but after I went into a relationship with whats now my ex, we talked alout cause they were good freinds. So me, and my two best freinds, who are always at my side started goig to her youth group and random events. I went to be with my gf, and my two freinds went cause I did. I noticed she had a tendancy to lie and cheat alot. Also to have an unhealthy infatuation with some guy at her youth group. After the school year I broke up with my gf, and she changed schools. So one day when me and my two freinds were bored out of our minds, one goes, lets text whats her face. So he did and he was a little inapropriate and she got real angry at him. So whatever. The next night she texts me and is like Im soo ugly no man wants me. I said your not ugly and treid to cheer her up. Well she finally said describe what you think is atractive. I said for one, face and stuff and dident think much of it. So the next day I start geting threating texts from the guy she was infatuated with. Apperently they are semi together. Hes swearing like crazy. He said I went to far and what ev. Long story short I told him to f*** off. A few weeks later, I get the same rotene with the same guy day after. I come to find out the exact same things is happening to my two best freinds. So I get this a few more times, but she starts ing instead. I would get the guy later, but it was random. I treid to play with her once but it was dumb, so I just acted like an ***. I ignored her for a looooooong time, and finnally talked to her again, but trying to steer the convo to a different place. It worked that time, but I got the same guy that night. I had treid to be nice and stuff to this guy for a while, but that night I flipped out and ended up scaring the guy shitless. He was such a dork. I never heard from him again. So I figured messing up her guy would stop her and she would stop. NO!! It continues to this day. The last thing I said to her was, LEAVE ME ALONE YOU FREAK! NO ONE WILL EVER LOVE YOU!!!!!!!!!!!!!!!!! Still hppens to my freinds to. We alll get the same text simaltaniously and the split from there. Soooooo yea. Sorry if this was a waist of your life. Any fresh ideas? Oh, and cant invole parents cause it would cause a huge mess.