The night makes a lot of shadows, but it's not totally dark. It only looks that way on the inside. Even late night has a certain ambient light to it. It's the stuff dreams are made of, or perhaps nightmares, for many of us. We think we see a monster in every swaying branch. Reflected light becomes protruding demonic eyes. We spend our lives behind technology, asking this lifeless thing to protect us from the night. When, instead -- maybe we need to embrace it. Feel what reality is like, when all the lights off, only to discover that this is when our true perceptual lights come on. The mask we force ourselves to wear is dropped, and we can see things as they are before we began mucking with the equation.
When you have to be out at this time of the night, you are told to ignore things like this. From an early age, your mother passes it off as a bad dream, or your overactive imagination. This is to keep reality stable for us. We learn to ignore those things that we can't explain, or use an easy explanation as a placebo. Even God used science in his miracles. He didn't create from scratch -- he used what was already there, planning in advance. The Star Of Bethlehem. Haley's Comet. With the whole universe there, who needed fancy omnipotently-generated light shows -- they already exist. God just pulls a Fatboy Slim and samples as needed.
So, even those things we can explain may have explanations on levels that we can't even perceive. The monster under our bed might be just a shadow, but it may also be the very monster we think it to be.