Need ID. Brown jelly looking things on rock

[cdouble]

I just noticed this a few days ago. It's a brown semi transparent sac (or 3) on the bottom edge of this rock I have. Not sure if it's a sponge or an egg sac to an animal in my tank. Anyone know what it is?

http://i.imgur.com/bh24VrY.jpg

[cdouble]

The antennae of one of my peppermint shrimp is peeking from behind what I'm trying to ID. It starts there and goes back and leftward.

[devimik]

Looks like a sponge from what I can see in that picture.

[Mark9]

Maybe circle what you want us to look at?

[cdouble]

I was thinking it was a sponge as well. I can keep a sponge no problem? Yet another filter in the tank?

Mark, I'm on my mobile phone so I can't edit the photo unfortunately. Towards the bottom of the rock where there is no coralline, right in the middle are some brown looking smooth growths. I did see a hole opening on the far right side of it but I have no clue what this could be.