Sea balls

Sea balls (also known as Aegagropila or Pillae marinae) are tightly packed balls of fibrous marine material, recorded from the seashore. They vary in size but are generally up to in size. In Edgartown, Massachusetts a longish sea ball around in diameter has been found. Others have been reported at Dingle Bay in Ireland. They may occur in hundreds and are composed of plant material, in majority seagrass rhizome netting torn out by water movement.
In recent years they have been shown to contain more and more plastic marine debris and even microplastics.