What is this mass growing in my zoanthids?

[cgd01]

I can't find nothing on Google. Has a mouth like a feather duster, but a white mass in my coral.

 

[rlman41299]

looks like just a common pineapple sponge

 

[TheEngineer]

That's what I think too.

 

[Ubans13]

i have tons of these and dont even know how they are getting in?

 

[TheEngineer]

Typical hitchhiker. They are harmless filter feeders. They'll help keep your water clean.

 

[cgd01]

Thanks everyone. Didn't want any harmful hitchhiker eating my coral

 

[mcarroll]

Can you turn off flow and get a clearer pic?

Could be a christmas tree worm....or a type of anemone that I can't recall the name of....had them hitchhike in to a retail system once....don't recall any severe problems from them.

(I don't disagree with anyone else's guess either so far, just adding some more possibilities.)