Actually, one of my cats does the same thing with watching the others cats using the litter. I don't mean that if he happens to be in the same room he will watch them. If he hears another cat using a litter he will run in and watch them. Really sucks for another one of our cats since he is bathroom shy.
She is very a big cat for her breed/gender and it is all muscle.
Also, she has razor sharp claws that can, no word of a lie, slice through skin very easily.
With regards to her being black, she likes to sleep in weird places like a closet so when you go to get a blanket or something all you see when you make noise is these two slit-like and creeps the shit out of me.