Well I'm 80% sure we have some form of a peanut worm. I can't really snap a pic cause he only comes out at night, and flashlights send him right back into the rock. However, he's a dark, round, "smooth" worm thing with a mouth and rings on him. Looking at Google and other sites, I'm pretty sure it's a peanut worm, except his "rings" are less vivid than other pictures. Are peanut worms good or bad, and does my description match up with the description of an aquarium peanut worm?