There I was, off the coast of North Carolina at a depth of about 20m (60ft) when the shadowy shape of the WWII wreck Caribsea came into view—but it looked almost as if it was moving! Upon closer inspection, it turned out to be a cloud of tiny bait fish completely covering the wreck. As they moved, the ship seemed to move with them; and then, out of the swarm, a massive, tank-like, gray silhouette emerged. It moved at one speed and in one direction, not altering its course an inch. I smiled so much my mask began to leak—it was a sand tiger shark.