What are these creatures in my refugium!?!?

[JasperDog]

Just noticed these creatures in my refugium. They started growing on my Chaeto and now they are everywhere in my refugium... what are they??

 

[MoshJosh]

Pineapple sponge. . . not bad. . . hopefully not bad cause I have like 1000 of them.

 

[HBtank]

Pineapple sponges

 

[ying yang]

+1

 

[BanjoBandito]

Only panic if SpongeBob comes out of one