Somebody Explain Why Cats Do This

This cat was not a choice. She was found in an alley in the mud, too young not be with her momma and covered in tics. I don't like cats. I didn't then and I still don't. The thing is, she wasn't a cat when she was brought to me, she was a kitten...and kittens are cute right? So now this cat lives with me. I've never had a cat in a home I lived in so there are some behaviors I'm not familiar with. Can someone please tell me why the f*#% she does this? Sometimes she will even his out of nowhere at literally nothing!

Here's the Video