Sponge crab (Cryptodromia sp.), 2 cm in size, over a sponge. Profile view, on black background. Sponge crabs (Dromiidae) cut out a fragment from a sponge and trim it to their own shape using their claws. The last two pairs of legs are shorter than other legs and bend upward over the crab's carapace, to hold the sponge in place. The sponge grows along with the crab, providing a consistent shelter. Underwater macro photography taken in Lembeh, Manado - Indonesia.