Little larva looking things on filter sponge

[Adam113]

Doing my water change today, and was cleaning my filter sponge that is right before my return pump. I found these little soft, slimy things on the sponge.

What are they? Couldn't get a very well exposed pic of them.

 

[Mike N]

pineapple sponges maybe?

 

[Brian W]

looks like Pineapple sponge to me too.

 

[USCG CWO]

I would third that. Sponges