Need an ID please

[RalphTheOscar]

What is the thing popping out of my rock next to the hidden cup coral?
http://i1148.photobucket.com/albums/o565/RalphTheOscar/20140902_230409_zps103309e8.jpg (http://s1148.photobucket.com/user/RalphTheOscar/media/20140902_230409_zps103309e8.jpg.html)

They pop out of the live rock all over the place, what is it and whats it doing, filter feeding?
http://i1148.photobucket.com/albums/o565/RalphTheOscar/20140902_230359_zps4966904c.jpg (http://s1148.photobucket.com/user/RalphTheOscar/media/20140902_230359_zps4966904c.jpg.html)

[Reeffwkeeper]

Check out http://www.masa.asn.au/masawiki/index.php/Foraminifera

Filter feeder.

[Sugar Magnolia]

It's a rock dwelling cucumber. They're harmless filter feeders.

[shesacharmer]

Hey Dude! You've got some pretty cool hitchhikers!