Need an ID please

[RalphTheOscar]

What is the thing popping out of my rock next to the hidden cup coral?


They pop out of the live rock all over the place, what is it and whats it doing, filter feeding?

 

[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!