Help identifying thing on new beloved coral!

[armyman16]

I bought a new frogspawn today from my lfs and when I was placing it in the tank all the polyps shrunk temporarily as expected and I saw a weird looking thing like in the pictures. It has a weird looking hand that comes out, it looks like a weebed small hand can see in the picture when it is inside. It goes out and does a scooping motion and goes back in. Can anyone tell me what this is and if it is harmful to my new coral? thanks in advance!

 

[ccCapt]

Might be some kind of tube worm that made it's home in the center of the coral. I am assuming it doesn't move from that spot.

 

[Flreefer]

The shape of it reminds me of those deep-water geothermal vent tube worms, that survive in 3000 degree temps, and noxious gases!! What a score! Jk, probably something similar though.

 

[mr_X]

I believe that's a barnacle.

 

[armyman16]

Yes ccCapt it does not move. Is it possible it could be a feather duster?