Alvepora White Fuzz/String?

[gr8pretender]

Is this normal on Alvepora? (White stringy stuff on the bottom).

 

[duberii]

Do they move? They almost look like some type of nudibranch

 

[MNFish]

I just noticed mine has the exact same thing. I have only noticed when it is not extended. I can see them blowing around in the flow so they look pretty well attached. Almost like little threds.