Strange Coral/Algae ID

[jeffmuse]

A month or so ago, I noticed a strange looking coral/ algae growing in the back of the tank. The "thing" is completely white, with no color at all... it looks like it is growing in darkness, but from the top of the tank I can see where SOME light is coming in, so I assume it is feeding the thing.

I have checked in on this thing periodically, and it appears to be growing slowly. It is not hard like an SPS, it actually has an almost rubbery texture to it. I have never seen anything like it, any help on ID'ing the thing would be appreciated.

Image of the base of this thing (shined a flashlight through a cave to take this picture)

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Here are a couple of picture from the top of the tank... you can see the thing going up the side of the over flow.

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[raz0945]

It looks like the sponge that I have growing in my tank.

 

[merkywater]

Jeff it looks like sponge actually. I actually have some similar in my tank.

 

[jef4y]

+1 sponge... they show up in the weirdest spots and look somewhere between freakish and cool.

 

[rolo65]

Looks like a sponge that I have in my tank too.....

 

[brianjfinn]

Yeah, it's a sponge. Nice tubastreas, by the way.