What is this growing on my rock

[alexhpc]

I was rearranging my live rock and noticed these three things growing, what are they?

 

[troywalkerphoto]

look like pineapple sponges

 

[BAD FISH]

I have them too completely harmless beneficial actually they are filter feeders

 

[Spsnut]

Pineapple Sponges look a lot like little pineapples: they are football shaped (rugby ball), white, with a don king tuff on top around the open. These are another common sponge.

 

[BellaGabriella]

pineapple sponges look a lot like little pineapples: They are football shaped (rugby ball), white, with a don king tuff on top around the open. These are another common sponge.

+1