Something sticking out of LR

[Jus_sum_guy]

Can anyone identify what the heck this is/are that's stick out of my live rock?

http://i260.photobucket.com/albums/ii12/jus_sum_guy/Mobile%20Uploads/IMG_20160317_212104_zpssf7eey46.jpg (http://s260.photobucket.com/user/jus_sum_guy/media/Mobile%20Uploads/IMG_20160317_212104_zpssf7eey46.jpg.html)

[iamfrontosa]

do they send out webs, or some feathery crown ? Either way they are no real issue. However, they do spread quickly. I started out my tank with dry rocks, and I still ended up with them.