Thing with white tentacles

[dwag1122]

This is on a good bit of my live rock from TBS. I’ve looked at their hitchhiker page and haven’t seen them. They’re stationary and appear to be gelatinous looking. Any clue what they are?

 

[NonstopSoda]

Im not quite sure what exactly youre looking at but i see a feather duster worm, some barnacles and i think a sponge? @ISpeakForTheSeas might be able to help but if you could circle what exact youre looking at that would be awesome

 

[PharmrJohn]

No expert here, but it looks like a feather duster.....

 

[dwag1122]

I circled them. It’s below the featherdusters in both pictures. It’s putting out tentacles about half an inch to an inch long

 

[dwag1122]

The one with the flat rock piece hanging off of it seems to pull the rock in and seal itself off when it pulls the tentacles back

 

[ISpeakForTheSeas]

I circled them. It’s below the featherdusters in both pictures. It’s putting out tentacles about half an inch to an inch long

Can you get some pics of them under white light? I can see the tentacles in the first one, but not much at all in the second.

 

[dwag1122]

This any better? The one on the left had constructed something out of sand and rocks

 

[ISpeakForTheSeas]

This any better? The one on the left had constructed something out of sand and rocks

Assuming they send out more than two tentacles, I would guess these are spaghetti worms (taxonomic family Terebellidae) - harmless/beneficial if so.