I purchased some live rock from one of our fellow members and found these "hitchhikers" while placing the rock in my new 55. I suspect they are sponges, but have never seen anything like it. 
There are four of them ranging from white to pale yellow in color. They are approximately 1/2 to 3/4 inches in diameter and look like someone took a golfball and cut it in half. Any thoughts? More importantly, are they "dangerous?"
There are four of them ranging from white to pale yellow in color. They are approximately 1/2 to 3/4 inches in diameter and look like someone took a golfball and cut it in half. Any thoughts? More importantly, are they "dangerous?"
