I had a cat that used to attack my mom, and only my mom.
She would wait for my mom outside, and either hide behind a building, in the garden (for a ground attack), or in a tree (for an air strike).
Cleo was a completely black cat and would usually attack at night, and especially loved attacking her if she was wearing a dress/gown
We lived in the country, and so we had a lot of yard and a lot of places for the cat to hide. She never hurt my mom, but liked to startle her.
Many times we (the kids) would see the cat, but wouldn't tell my mom, so that we could watch the cat's evil plot unfold.