Well, I'm curious enough that I followed up on the 'sea squirt' suggestion and looked up what I could find. These might be sea squirts, but I was unable to find a picture of one like these to confirm it (the pictures I did find were far more beautiful or bizarre than these cottony fuzzballs).
Sea Squirts, otherwise known as tunicates or urochordates, are in the same phylum has humans (chordata). Only the very young tunicates reveal their relationship to other chordates. The tadpolelike larva has a globular body and a tail used in swimming. When it attaches itself to the seafloor, however, it loses the tail, notochord, and dorsal nerve cord. The adult is covered with a protective covering called a tunic and feeds with its gill apparatus.
Kind of cool - it needs its 'brain' to find a home, then when it no longer needs it, it 'eats' it.