What is this white squishy hitchhiker?

[yuzu]

I found this when cleaning a frag plug. There are at least 2 in the tank, about 4-8mm tall and soft when prodded. They have some feather-looking tentacles at the top which don't seem to retract. I'm fairly new to reefing and worried I have another pest on my hands.

 

[obelisk29]

I found this when cleaning a frag plug. There are at least 2 in the tank, about 4-8mm tall and soft when prodded. They have some feather-looking tentacles at the top which don't seem to retract. I'm fairly new to reefing and worried I have another pest on my hands.

Pineapple sponge?

 

[Crabs McJones]

Agree, pineapple sponge Harmless filter feeder.

 

[yuzu]

Ok thanks, that looks like the one. I'm having some trouble with bryopsis and glad it wasn't bryopsis 2.0.
Cheers!