Is this a bad hitchhiker?

[NewReefMom]

I am relatively new to the reef/saltwater hobby. Could anyone please tell me if this hitchhiker is dangerous to my tank?
A little background, my tank has one live rock and 2 dry rocks. I first seen it on the live rock but now I see it on my dry rock as well. It seems to have tenacle like arms that can retract.
I tried Googling but could get a definite ID.
Any help or expertise would be greatly appreciated.

 

[Reefer5640]

That’s a little feather duster. It’s good. It’s a filter feeder. Means your tank is doing well and getting established. They can come in different colors too, though white/tan/clear seems to be the most common. I get red ones in my tank too.

 

[Zoa_Fanatic]

That’s a little feather duster. It’s good. It’s a filter feeder. Means your tank is doing well and getting established. They can come in different colors too, though white/tan/clear seems to be the most common. I get red ones in my tank too.

I’ve got the red ones as well. First person I’ve seen say that. Do yours get big? My white ones are massive but the red ones I have have stayed little so far

 

[Reefer5640]

I’ve got the red ones as well. First person I’ve seen say that. Do yours get big? My white ones are massive but the red ones I have have stayed little so far

Yeah they are definitely the smallest

 

[WheatToast]

That’s a little feather duster. It’s good. It’s a filter feeder. Means your tank is doing well and getting established. They can come in different colors too, though white/tan/clear seems to be the most common. I get red ones in my tank too.

Second! I have red tufted ones, long white ones, and Spirorbid worms.

 

[reefz]

Those are awesome.