Opaque Feather duster like critter

[Drummingbaker2010]

Hey guys. I was performing a water change on my tank this morning and I notices a small critter in my refugium with the head of what looked like a feather duster, but with a balloon like body and it was white and see through. does anyone know what this is? is it bad or good? should I remove it?

 

[Cell]

Pineapple sponge. No worries.

 

[Cell]

Well, most likely a pineapple sponge. Can't be 100% without a pic.

 

[Drummingbaker2010]

This is what I found.

 

[Drummingbaker2010]

does anyone know?

 

[WheatToast]

This is what I found.

Looks like a retracted Aiptasia anemone.
https://www.tfhmagazine.com/articles/saltwater/the-salt-mix-full291505

 

[Cell]

Not pineapple sponge. Hard to tell what it is though. What angle are we looking, top down? Tentacles look more packed closely together than the typical aiptasia to me.

 

[Drummingbaker2010]

yes, top down view.

 

[Cell]

Looks like some sort of nem to me from that angle. I'd scrape it off with a credit card or something and get a closer look if possible.

 

[Drummingbaker2010]

Looks like some sort of nem to me from that angle. I'd scrape it off with a credit card or something and get a closer look if possible.

I'm just trying to figure out if it's a bad hitchhiker or if I can leave it alone.