We found this pugnacious little crustacean giving us menacing looks as we built castles with, as he would have us believe, his sand. His bravado failed him, however, when he saw we were willing to fight for it--nothing but an armored, but spineless, bully was he. Adam had him scudding to the dunes as fast as his eight legs would carry him. We finished our castle unharried.
When Adam runs, he pumps his left arm more vigorously than his right, and manages impressive lateral movement of his bottom. We took quite a few photos of this adorable phenomenon!