I am writing a young adult romance (m/f) novel where her 'best friend' wants to destroy her. She has decided to take her (MCf) boyfriend (MCm) before she kills her. She has tried to set MCm up so MCf would think he is cheating on her. When this does not work, the antagonist tries to embarrass him at school. She releases multiple rumours about the pair. She even tries to convince people he has assaulted her. The problem is I cannot imagine what other rumours she might use. Oh, did I forget to say she is not mentally stable.