[Cyclone]

When your eyes play tricks on you, that is an optical "misfire" where your eye is sending false information to your brain because it is trying to interpret something it has picked up on - like a shadow or something moving briefly out of the corner of your eye - and make sense of it. Usually these are things you see briefly out of the corners of your eyes, and as soon as you try to focus on them they disappear. This is completely normal and happens to everyone.