The Final(2010)

A group of outcast teens form a plan to get revenge on the mean popular kids that torment them at school.

They plan a costume party at a remote building and secretly invite all of them not letting anyone know they are hosting it. They make a point of not inviting the one “cool kid” (Andy) who is nice to them and sticks up for them, but he shows up anyway. Everyone shows up at the party in costume, the cool kids not realizing the outcasts are even there. Suddenly all the cool kids pass out, when they awaken they are all shackled together in the middle of the floor. The outcasts start to torture them, or force them to torture/Maim or kill each other.  Their plan is going well until one of the outcasts frees the nice kid (Andy) and let’s him run away.

The outcasts turn on each other killing one of their own for letting Andy go. Andy runs and gets help.

In the end several of the cool kids are maimed or dead, and all of the outcasts die, by either killing each other, being killed or killing themselves, having formed a suicide pact before the party started.

The maimed cool kids are left to be the outcasts, be stared at and picked on.