These are cool little crabs that scurry across the sand. Sometimes called sand crabs, the make a burrow in the sand to spend the day and come out at night to feed. They can sometimes be seen during the daylight hours and a fun to watch.
We took a walk on the beach one full moon night and saw hundreds of these crabs. Unfortunately, there were thousands and thousands of no-see-ums in the air and we made a fast exit from the beach.
FOG sez: I have been accused of being a bit crabby at times.
However, I have never been accused of being hard to see.