This struck me as some sort of beach art left for the next people who wandered through. It's clearly not 'accidental' and I can't think of a reason animals would construct something like this. So... it's just nifty beach art!
These trees break my brain. They're obviously dead now, but they were clearly once hugely thriving trees. In the sand. At the water's edge. How does a tree grow like that in the salt water of the gulf? In the sand instead of soil of a beach? If you look closely you can see that they're now clearly woodpecker condominiums. Didn't see any of those inhabitants that day, but there's still something striking about the dead tree, the sand, the water and the cloudy sky that looks warm to me.