Anyone able to ID these strange things?

[ConorE]

As above. Tank has been cycling for a few weeks and rock was moved from previous tank.

The one that looks like it is squished in the rock I originally thought maybe starfish but it's beenthat way for weeks now and has only grown bigger. Not moved.

 

[F i s h y]

Top picture is a feather duster worm. Not sure which thing to focus on in bottom picture happy reefing!

 

[vetteguy53081]

I see duster worms and hydroid. Using a syringe, mix kalkwasser powder into a thin paste and inject into the center core of each one. You can also use gel superglue but can get messy

 

[ConorE]

Top picture is a feather duster worm. Not sure which thing to focus on in bottom picture happy reefing!

Thanks guys.. are these good guys or a nuisance? I have quite a lot of the feather dusters about 5mm in size.