I spotted this Jeweled Anemone Crab scuttling over some very uneven rock and coral, but it was still able to move at a pretty good pace. The Jeweled Anemone Crab is a hermit crab, meaning it lives in a snail shell, either one it found unoccupied, or one from which is evicted the current tenant.
This one looks to have found a colorful shell, but looks are deceiving. The shell isn’t visible at all, because it’s covered by at least four large anemones! These are Calliactis polypus anemones. They give the crab some protection because, if disturbed, they shoot out stinging threads. In return, they get transportation and possibly scraps of food from the crab.