Anyone Know What These Cocoon-like things are?

[StillerNat]

I see these everywhere under frags and on some rocks. i never seen something like this before. it looks like a cocoon and they are easliy pulled off. some are big like a tic-tac and others are small. i dont know where they camr from and i haven't seen them before the other day. i dont see anything coming out of the end of them.
any ideas?

 

[lurchw00t]

Pineapple sponges?

 

[mscarpena]

I agree. Harmless. If you have too many though you have high nutrient load.

 

[ClamsOnDemand]

Sponges they pop up mostly in the areas of your tank and overflow that arnt getting much if any light. Pretty common.

 

[AJSTITAN14]

I have heard them called Pineapple Sponges and Q-Tip sponges.

 

[Sugar Magnolia]

Scypha ciliata.