You were looking at sticks or something, the deer never existed. I have seen things from my stand I swear are deer bedded or antlers sticking up and so on. The sun shining in the woods creates illusions that look like things they aren't. If you hit the can and got ZERO reaction from 15 yards I bet there was no buck. On the other hand........
If you swear you saw a buck, you saw his head and eyes and ears, then maybe he did something I have only seen two times in my hunting career:A belly crawl. I have seen two different bucks evade hunters using this maneuver. They use it as a last ditch effort when they are caught in extremely close quarters with a predator that they think does not see them. It is a tactic to get a little distance between them and the predator because they feel that revealing their position is not a good idea at the moment. Maybe it goes back to when big cats were a major predator of deer and had the ability to pounce in such close proximity.