Who is hiding in this cave?

[matlet]

Hi,

I moved one of my powerheads in the tank and it stimulated my elephant ear mushroom to close. Under him I saw some translucent gooey looking stuff covering an indentation in the rock. In the center is a perfectly round hole/tunnel going back into the rock. The hole is approximately 1/4" in diameter. You can see the hole in the attached picture - sorry about the resolution - had to use my phone camera since digital camera is in the shop.

Any thoughts on what it might be and should I be doing something about it?

Thanks,

Mark

 

[george]

Looks like it might be a sea squirt, but likely a sponge of some sort. They come in an abundance of colors. If I had a camera that didn't suck, I'd post some pics of the 4 or 5 different varieties I have in my tank.

 

[flipturn88]

Looks like some sort of a tunicate to me? A sponge is another possibility, as George said, but it's somewhat hart to distinguish from the pic.