I think you are comparing apples and oranges.
Using your spider analogy..
"There seems to be orderly direction for the existence of what we see. Certainly the reality of the Second Law of Thermodynamics points that something continues to run contrary to what we know, thus, the POSSIBILITY of a God that exists by what we are seeing is backed up by reason.
So your unicorn example isn't valid and an overused two-step so as not to address that people who say "God does not exists" aren't required to prove their position.
Ken, the ancient Greeks proposed the existence of gods to explain the winds and rain -- because they couldn't explain them without. Yes, one must suppose it possible the winds and storms were pushed around by deities -- but then we learned a lot about how climate works on this planet (and others, now!), and the deities weren't required.
If you are going to base your "possibility" of God on not knowing the ultimate reality of the cosmos, then you place your God squarely in the headlights of science, and they just might one day explain it away.
And in any case, just making the God assumption puts you in another strange place, in that you can't explain what God really is, how God is what it is, and what possible purpose such an entity could possibly have in creating a cosmos such as we live. All of those are a complete and total mystery to you. You have no possible conception of what, how and why an entity without time, substance and form suddenly (and without time, it must have been suddenly) needed to create time, substance and form. No explanation at all. Nor can you, in your theology, even begin searching for one, for these things are explained away as being beyond our ability to understand.
At least science is making the effort to understand our cosmos -- and its origins. And I can tell you this -- if science does eventually discover some trace of this god being involved in creation, science will admit to it right away.