From his aerial perspective, Sam observed activity a few dozen meters in front of the panzer. The earth was mounding. and Sam’s first thought was that concealed enemy troops were breaking cover. The notion was soon dispelled when he saw the soil moving by itself. Rocks and pebbles rolled toward a central bulge that heaved itself up, making a wall across the panzer’s path. Before Sam could warn Begay, the Thunderbird plowed into the weird obstacle.