During an early dive once my buddy saw two crabs sharing what appeared to be a passionate and fairly intimate embrace. Wanting to point out sweet dungeoness luvvin to me, he pointed to the crab, and then started thrusting his hips and pulling his arms back to his sides over and over, in a delightfully juvenile "Look, they're DOIN IT!!" hunka-chunka dance. Needless to say, SAC rates rapidly rose and all manner of buoyancy and trim went to s#@*. Where is your uw camera when you need it?