White slug type thing or sponge?

[MRRBW]

I cleaned out the skimmer portion of my box filter and pulled out the plastic grid that supports the skimmer and found it full of these white soft/gooey things. They don't move fast, are attached with what seems a slime layer and they mostly protruded out away from the foot attached to the grid. Any thoughts on what these are?

 

[ReefMadScientist]

Pineapple Sponges. Completely normal and safe.

 

[Reefing Madness]

Pineapple Sponges. Completely normal and safe.

Agreed

 

[MRRBW]

thanks. Wasn't worried about them being harmful, just curious as to what they are. I find the littlest random findings in my tank sometimes to be the most interesting part of having a reef tank. Thanks guys!

 

[un5tab1e]

Pineapple sponge. Asked the same question last week when I found them all in my skimmer and return pump.