Is this a jelly fish?

[Ehgemus]

Is this a jelly fish or am I stupid? look at my first pic. in my gallery,
It is on the left side of the rock sorry I can't get a better Pic. My tank was just set up and the 50 lbs of rock is been in there for a week. It is clear looking skin with milky inside stuff. what is it?

 

[Ehgemus]

This rock was scrubbed well before being put in the tank so it had to have come from the inside of the rock.

 

[Lev F.]

I think It's a sponge.

 

[Ehgemus]

Does a sponge move freely with the movement of the water?

 

[romunov]

Could be a tunicate. A better picture (flashlight! ) would be helpful. :bigeyes: