What is this?

[Ro Bow]

So I found this weird thing, and dont know what it is. My guess is feather duster babies but idk. I've never encountered these before. Tank inhabitants that could have made this: Feather duster, xenia, turbo snail, astrea snail.

 

[Cincyreefer513]

It looks like a pineapple sponge.

 

[mdb_talon]

looks like pineapple sponge

 

[Dburr1014]

Pineapple sponge

 

[Ro Bow]

ok, cool. I did not expect that! Thanks for your replies