My experience has taught me that in *most* situations,

HR IS NOT YOUR FRIEND.

I agree with Mrs. Mania that killing the offender with kindness is a great strategy. Whole religions have been based around this principle. Plus, you get the good feeling that comes with being....good. I realize that's small potatoes compared with revenge fantasies, but sometimes when bullies realize they're not jerking your chain, they go...elsewhere.

And finally, plan your escape. This situation is crazy-making.