A form in the shoreline

"Have you ever stared out into the fog? Really stared into it? After awhile you will notice that it is not just a static blanket of gray, but there is movement in it. The fog moves about, creating shadows within it, it feels as if there is something moving in it, just far enough that the fog disguises its shape so that you cannot discern what it is that is out there. nine out of ten times it is nothing and it is just the fog playing tricks with you, but its that odd chance in there that will sneak up on you when it does happen, and the brief period of tension when you begin to see it more and more clearly makes it all the worse when it comes into full view."