People that had toxic friends that you cut off, what are your stories?

I had this friend, let’s call them Kate. Kate looked very friendly and trustworthy. You could also say Kate was someone, you’d wish to be friends with. But something about Kate which not everybody noticed was that Kate would get close to people and gain their trust, gaslight them into thinking that she was worth every other friendship they had, and break other people’s friendships to get her own work done. I sometimes believe that Kate doesn’t even know that she does this, it’s just Kate’s nature.