beaches

[mulburger]

what are the spirals of sand on a beach that look like worms

[grandmabundy]

sand has has been through lug worms

[Dusky]

Lugworms eat and pass the sand, making the worm cast you describe.  They then burrow along under the sand and up again.  For each worm cast you'll find a small round dent in the sand about 6" away where the worm has sucked the sand down from underneath.  It then lies there passing sand through and absorbing nutrients from it and pumping water through itself to absorb oxygen.

See here: http://www.lanecc.edu/science/Estuary/LUGWORM.102.html