That sounds scary, for sure.
I've had a few experiences of that sort. Though they were weird they usually seemed pretty benign. Definitely none as scary as yours.
The strangest incident involved me waking up in the morning, but instead of moving I just lied in bed awake. That was usually the situation in which this sort of thing would happen.
I had the sudden awareness that something was sitting next to the bed beside me - not sure how I was aware of it, I just was. It was small and black, and seemed to me to be a black cat. It was silently observing me.
I also had the awareness that there were holes of some sort in the walls around me, lots of them, about 3 feet in diameter. It was through such holes that these black cat-type things would pass.
I wasn't scared at all about the scenario I was in, just impartially curious. Then after several moments I had the thought, 'Wait, I don't own a cat' - and at that moment I sensed the black thing quickly recede back into the wall. My awareness of the room quickly transitioned to my normal awareness and I sat up, hearing what sounded like running on the opposite side of the wall.