my co-worker has absolutely tried to sabotage my reputation and work, to the point that even her own boss has apologized to me when she's not around and stated that she is very very wrong and she has been told by him to stop her nonsense. But it never truly ever stops; She's just the type of bitter person who will always find something or someone to complain about.
Catch them off work and explain the Finer points of to life to them.
Will find out what is his or her problem
Do it first.
Rip them to pieces.
make their life a livin hell
Express your feelings with your guys boss, and request a meeting with your sabotaging co-worker to end the situation.
report them for harrassment
I smile and befriend him/her.