A cat came into my house unwelcome and ran up the stairs window open

HI there I dreamt last night that there was a black cat with yellow eyes came into my old childhood home through an open window. (IRL it is a cat that lives locally that keeps coming to my window as I have an indoor cat of my own.) In my dream this cat got in through a downstairs window that was open and my own cat was very angry at it it started hissing and spitting at it but the black cat did not seem to bother it was only interested in going upstairs in my old house, I called on my mother to help me get this cat out of the house but she told me not to worry about it just to leave it it couldnt do any harm. I was very afraid of it and upset that my mother would not help me and I was worried for my own cat. I woke up feeling quite anxious. Any idea what this could mean