I was bullied by a co-worker. Having worked in the computer field he thought he was smarter than me - and he probably was - but would yell at me and call me names when nobody else was around and was nice as pie in front of most everyone else. One day when he was being sickeningly sweet in front of a superior I asked him (in front of her) why he was nice when other people were around and nasty when they were not. He had no words so I went on to tell him that I was going to start wearing a recording device when we worked together so I could prove how nasty he was to me when nobody else was there. He stopped treating me so badly after that. Sometimes you just have to bully the bullies.