This is an interesting illusion that we have categorized under disappearing effect illusions. In the image, you can see so many tiny red dots. What you have to do is pick up any of the red dots. Now, just stare at that dot for some time. What did you notice? If you keep staring for a few seconds, all the other red dots will disappear. Now try the same with another dot. This stands true for every other dot as well.