Spoinid worms?

[D'sreef]

So I was moving around a piece in my small aquarium, and found these soft tubes with some substrate mixed in. They are almost gelatinous. I looked through the hitchhiker guide and Spoinid worms matches the closest, but I did not see anything popping out of said tubes. They wipe off very easily, and I investigated and it seems they are on everything that is in the sand. Any clue guys?

 

[Tikki]

Possibly digitate hydroid?