Unknown tentacles critter

[Mstan]

What is this critter that extends it's testicles from the base of my frogspawn. I also have it on a zoa frag. Very thin hair like tentacles with dots that retract when touched and extend out when left alone. Should I be concerned?

 

[guylaga]

Spaghetti worm, they are harmless.

 

[Double monti 61]

Not a spaghetti worm it’s a cirratulid (hair worm) good for the system I have many living in my substrate.

 

[Hadla]

Surprised no one mentioned the autocorrect to testicles