Thanks for the response so far. I'll answer some questions.

In group situations she tends to be a controlling diva. She can sometimes be curt to our boss.

Okay here is a type of mental game she plays. When I approach her to ask a work related question she's extremely harsh, abrasive, rude. Condescending comments like "What do you want?" "Make if quick I'm in a hurry!", "What are talking about?" Very dismissive.

The other day she had a little tirade and lit into me when I gave her a suggestion and she snapped.. "I don't like to told what to do!"

After her temper tantrum was over she became immediately over friendly with my other co-worker who witnessed it. Really befriending him. It was like she was trying to make it seem to the other co-worker ... See, look I'm not really a b***h look how overly nice I am to you!. It was weird, it was bizarre. She was acting like a stuck up spoiled brat, and a B***h.

When I first started working there she liked me and wasn't getting along with another female co worker(now their best work buddies), and when they'd have their spat, she would come over to my desk and be overly friendly to me.

So what to you call that in psychology when someone lashes out at one person and then immediately acts overly friendly to other person in the same room? Is she just twisted? A psycho? or deliberately playing a game? Is it part immaturity? Why do you think she treats people like cr*p, and talks down to them?

Interestingly, that same co-worker she "loved up to" after she lit into me has experienced her curt and condescending tone when he has approached her at her desk. He's even overheard her being rude to her client's.