you know, all those names. and it just like -- they are always calling me, and it makes me want it do it. >> it is just this new rage. this girl fighting. and they feel like they have to prove something. to fight. i just hate to see girls fighting, taking it to that level. >> but on march 25th, 2011, sierra decides to do just that. when she agrees to fight a female classmate in the woods after school. >> i had a group of people. she had a group of people. i showed up there first and there was already a lot of people there. like double the amount of people i had with me. i was just -- i don't know -- shocked that there was that many people that knew about it. and a lot of people were older people too, like high school. so i was like, why are all these people here. >> with dozens of kids egging them on, sierra and the other student begin to fight. see year's friend captures the disturbing scene on her iphone.