Just kidding. This is one of the many types of sea cucumber we have here in Hawaii. Sea cucumbers are quite common here, and are a sign of a healthy reef. They are sort of the vacuum cleaners of the reef, with tentacles in their mouths that sweep through the sand picking up sand and detritus. As the sand passes through they digest whatever they can, this is one we found "caught in the act" of redepositing the sand back on the reef.
I'm not big on scatological references, but we do have customers asking what that "string of pearls" was laying on the reef on occasion, so I thought I'd post the picture as it answers that particular question.