New growth on my LR

[calikit]

I have found something new on my LR and was wondering what it is and if anyone knows about it. It is white and growing from my LR. There are 2 of them. Sort of looks like an anemone, but I can't get close enough to see it and it's still small.
Thanks

 

[vegas made]

ya mine almost looks like that and its like a little cotton ball almost i have that too on my LR inly like 10 of them

 

[steve24]

a harmless sponge ...

 

[royal gang]

I got 2 immense ones.