Sleep paralysis is a fairly common experience for me. There are periods over which it occurs with greater frequency than others. In the vast majority of cases, I undergo sleep paralysis when I'm home alone. It even happens when I think someone else is in the house but then discover upon awaking that nobody else is there.
I have numerous experiences I could share. For instance, a particularly chilling episode occurred when I was in college.
While I was attending UT, I lived at home with my parents and worked part time at the local grocery store. This arrangement was far cheaper than moving out on my own, and it allowed me to pay as I went and graduate without accruing any debt.
One afternoon, I returned home after class, and decided to take a nap on the couch before work. Shortly after drifting off, I found myself awake but unable to move. It took great effort just to pry my eyes slightly open, and scan the room between two thin slits. I became a little unnerved when I wasn't waking up as quickly as I thought I should be -- this wasn't my first bout with sleep paralysis -- so, thinking my dad might be home, I decided to try to call for help.
I couldn't form actual words, but I was able to generate a sort of grumbling noise in my throat. It seemed inconceivable that someone, even if he or she was in the house, could actually hear me, Nevertheless, a voice replied: "I'll be right there!"
It sounded just like my dad. I remember feeling relieved that help was on its way, and saying silently to myself, "Thanks, dad."
As soon as I spoke the words, the voice came back, "No problem. But there's something you should know: I'm not your dad."
I awoke immediately, completely alone in the house.