What's the worst way a friend backstabbed you?

OK this is a long one! Ok so, me and a very close group of friends everyday after school would go into an unused science room at our school and hangout, now this was obviously against the rules saying it's "not safe" but we continued anyway because we loved it there, we talked and talked and it brought us closer together as friends, at least until a new girl came into our small closed off group, one f my friends begged and we gave in thinking that this girl had changed as we knew her before and she wasn't the best person to be around. Anyway it started OK she came with us to the science room but would only talk to one of my friends and then wouldn't let us talk to her. Then to make matters worse she started a rumor about me and all my friends about everything we did and tried to take one f my friends away from us so she could be all hers. Now we were nice and she told us secrets so we considered her a friend, but then things exploded, my friends were being abused by her and I wanted to come up with a plan, but it was too late one day everything came out and we all got suspended for a day, but then everything got worse when later said that we watched porn in there when in reality she made us watch it or else she would tell about our hangout which wasn't good, needless to say what she made us watch was just bad and downright wrong. We weren't suspended more but for the rest of the year rumors spread like wildfire and we had to explain ourselves to the school principal, luckily we were able to sort things out and finally reveal the truth and get the girl in more trouble, she ended up being forced to transfer schools.

/r/PlanetDolan Thread