Ghost crabs are called that because they are camouflaged to slink around at night.  Found on the upper beach out of the intertidal zone, they blend in with the sand and run in all directions.  They eat clams, birds' eggs, mole crabs and most anything else they can scavenge.  They have to enter the water periodically to rewet their gills. 

More active at night, the ghost crabs burrow deep holes to hide out.  The holes can be as much as four feet deep, and provide shelter in the winter when the crabs become dormant. 

Ghost crab holes can be found on Masonboro Island, but on the more-populated beaches you probably won't find ghost crabs in abundance.