I work with this woman who is older than me (I'm in my late 20s, I think she is around about her 50s). When I first met her she seemed fine, she was warm and chatty. She said something a bit odd to me, but I just shrugged it off. When we worked together just the two of us she would snap at me and her attitude overall was defensive and I didn't really know where it came from after her being fine before. I thought maybe she was having a bad day but it contuined like that and didn't change. I would ask her simple questions to get to know her better and she would give sarcastic or eye rolling answers. She didn't make any effort to get to know me. Other people have implied they've had issues with her also.
So the snapping and general bad attitude contuined. She would also take credit for work both of us had done. She had also only recently started and I had to show her the ropes, but she would tell other members of staff she had been there for a year. Then one day she randomly approached me and started making comments about my weight. It really upset me because it was so random, she walked straight over to me and started saying stuff. It caught me off guard a bit. I reported her but my senior said her attitude is her sense of humour.. when I didn't think any of it was very funny..