Ya!!! cat sometime do hv tht frightening look in their eyes especially when they give tht staring look in their eyes like seeing thing tht is not there. But sometime if u look clearly u will be able to c what they r actually staring at, it cud simply be just a tiny insect tht we r no able to notice earlier. There's quite a number of time when some of my cats just give tht frightful look over my shoulder looking out at the glass door & when u turn to c what it is, there is nothing there, I guess it might be due to them been able to pick up sound tht we r not able to hear which cud actually be the cause of their sudden reaction to some happening outside the door.
Long ago when I was young I read about an article of some scientist researching on the existence of astro body on a man who can easily command it to come out. They will hving his cat in a room somethere a 1000 miles away & hv him wire up to monitor any happening to his body & almost immediately when they notice something happening to him & also at the same time his cat was reacting to something in tht room. It's not mend to frighten anyone but to say there is a great possibility tht our feline friend can c thing tht we don't.