@dlp11, could be. But could also be a very baby tubeworm. Hydroids are often golden brown and occur in clusters. If you can see distinct fronds on the plume, tubeworm. If fuzzy-looking, hydroid.
@ssick92, not so sure: it could be a spaghetti worm; the rock is quite barren of prey, so if that's a eunicid it's a) the smallest on record and b) it'll start coming out looking for food. WHat particularly makes me think not-a-eunicid is the bluntness of those arms. Eunicids are kind of wickedly pointy, and they're fairly quick and agile and crawl about. If those tubelike structures don't ever move, it's just a little spionid worm's hard casing. Spionids have two pale hairlike tentacles that come out to fish for dirt or food and they excrete by passing a tiny bit of poo out between the two tentacles: interesting little critters, decent cleaners.
@ssick92, not so sure: it could be a spaghetti worm; the rock is quite barren of prey, so if that's a eunicid it's a) the smallest on record and b) it'll start coming out looking for food. WHat particularly makes me think not-a-eunicid is the bluntness of those arms. Eunicids are kind of wickedly pointy, and they're fairly quick and agile and crawl about. If those tubelike structures don't ever move, it's just a little spionid worm's hard casing. Spionids have two pale hairlike tentacles that come out to fish for dirt or food and they excrete by passing a tiny bit of poo out between the two tentacles: interesting little critters, decent cleaners.