Help id some type of small coral or anemone

[Saratj1]

I have in my tank a small black "item" who has two "heads" and white tentacles that open rarely maybe twice a week that I see. It's attached to some live rock under some red algae tree, it's kind of exotic looking but only black body with white tentacles, you cannot see the white when it's closed, you can hardly see it at all when it's closed. Help Id please. I'm putting some phone pics and then uploading some camera pics in a minute.

View attachment 77592

 

[Saratj1]

here's a better pic, where I kinda cropped and focused at the item I'm talking about, one of the tentacles is right at the tip of the damsels top fin and the rest are in a circle the dominos fin being at 8 o'clock, I also noticed possibly some orange coloration with the white but very small may just back ground stuff, If any of that helps.

 

[Saratj1]

No, ideas?

 

[ccCapt]

Not sure exactly what you are referring to, but look up hydroids.
Hydrozoans

 

[Saratj1]

View attachment 82203

Another pic, they rarely open so hard to see, but for some reason they all decided to come out today after a pwc. I have about 5 all together.

 

[Saratj1]

I have id'd the mystery creature. It is a burrowing sea cucumber. I have about three of them on a live rock.
Neothyonidium magnum