Help with my scary story year 9?

okay well i have to write a scary story for english, my idea is have a schizophrenic/multiple personality disorder girl who was abused and abandoned by her mother and father. she hates how everyone wastes there lives and takes everything for granted. and waste their lifes with booze and drugs and are possesed by money. She takes one person from each of these catagories and gives them a test kinda ;like the saw movies but the test has to demenstrate they can change there ways. E.g a choice between losing 1 million dollars or losing a leg but stuff a bit more inventive and has a better twist to it, please help. Or if u have anyother suggestions feel free to share :)