What Type of Invertebrate is this?

I'm not sure how this works but I'll give it a try. A few weeks ago I purchased a live rock with some corals on it(not even sure if it's a coral or what) hoping that I could bring it home and bring them back to life. Well they are do really well, there were only two, and now it's grown into six, the only thing is I haven't found out what they are, and I don't know how to describe them to narrow down the search on Google. But please look at the picture and see if you can tell me what it is, and maybe a little bit of information on it. if you click on the picture it'll give you a bigger better image. Thank you for your help.

 

Some type of brown palys would be my guess

 

look like your typical red/brown polyps/ palythoas

 

Found it

Thank you for your help, I was able to find what it was based on the answers you guys gave me. It's a Palythoa Tuberculosa. Here is the link to the web-site that I found that has the exact same specimen as mine.
Zoanthids

Again thank you for all of your help.