Little White Creatures in Sand?

Might have been an isopod. Isopods are crustaceans along with copepods and decapods. The decapods are crabs, lobsters and shrimp. Copepods are either plankton or parasites on fish. The isopods are the most terrestrial crustaceans. People encounter them in their gardens as sow bugs. Isopods generally eat decomposing organic material. There are a variety of semi terrestrial isopods found near the shore. Another crustacean found in the sand is the mole crab. It is a decapod and has a pill shaped body with a very smooth shell. It is only found in the surf zone. It filter feeds as a wave rushes in and then burrows into the sand as the wave recedes. Ghost crabs are also very common along the beach but are recognizable as crabs. They run very quickly sideways and live in small holes in the sand. Ghost crabs are scavengers.