It's not a snake. Or perhaps I should say it wasn't a snake since this picture shows only what's left of an Eastern Slender Glass Lizard (Ophisaurus attenuatus longicaudus).
Glass lizards are large, legless lizards. This particular species ranges in size from 22 to 46 inches. (I placed my pen in the picture so you could get an idea of the size.) Their tails are quite long, extremely fragile, and usually break off quite easily. Sometimes the tail will break into several pieces. There is even an old wives' tale that this "snake" will break into pieces and then join itself back together. If you look at the tip of this one's tail you can see that it is regenerated. I seldom find one of these lizards with a completely intact tail.
So what happened to this one? Why didn't it's tail break off and distract the predator so the business end of the lizard could escape? And why didn't the predator finish it's meal? All good questions for which I have no good answers.