I had lived with a roommate in the gulf town of Orange Beach, Alabama mid 2009. He owned a cat that was very loving, full of energy, and from what I found out; very perceptive.
I was alone, just me and the cat, I was making a sandwich on the kitchen counter, his cat was in the livingroom. The Kitchen and livingroom are open to one another.
I laughed as Ninja ran about the hall and livingroom doing goofy things. But suddenly she stopped, looking like she was following something with her eyes.
At the moment I really didn't think much about it because animals can spot a tiny insect and react like its the most astonishing thing they've ever seen.
So, I continued the sandwich build, but when I looked up again, she began to rub her head on something that wasn't there. So much that her second head rub now included her body which was leaning hard to the right while in motion.
Like she was familiar with whom ever it was with sheer affection and was rubbing on someone's ankle. The lean-in was unexplainable, her body was anywhere near her center of gravity, yet she didn't fall over.
This is not my first experience with the paranormal there at his home.