Membranipora membranacea, otherwise known as Moss animals.
Bryzoans are colonial microscopic animals that live in both fresh and salt water.
Like sponges, they are filter feaders.
They can be mistaken for coral and often grow on algae, rocks, shells, and ship hulls.
The colonies can range from millimeters to meters and the induvidual, called a zooid, is usually less than a millimeter in size.
Although the colonies are considered nuisances, they produce a remarkable variety of chemical compounds, some of which are being tested for posible medicinal uses.