ID me Macro shot.

I borrowed my wife's camera. Mine doesn't do good macro shots. Even hers could be better.
So I found another coral?? on a piece of liverock.
I looked at it under a magnifying glass, but I am at a loss. I thought it was algae, but it doesn't feel like algae.
It has been in a plastic bin full of liverock for a couple of months, out of the light. It has had circulation and heat.
It is about 1/2" across and a brilliant forest green.
It caught my attention when I pulled the liverock out and it felt slippery/slimey just like the echinophylia I posted about previously ("Is this a coral?" post)
So, can any of you veterans help me identify it?
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The first two pics are without a flash.

Being that it had no lighting, best bet is, it is sponge.
Good stuff. I had a rock a long time ago that had this green, yellow and red type of sponge on it. Looked really cool.