Interesting green hitchhiker

[cooper13]

So I found this hitchhiker o some live rock last week. At first it looked dead and seemed very dried up and waxy. Now however it looks to be growing again. Here are two pics (second is from my wife--I'll have to check it out tomorrow when I get home from from LA):
Before:

After:

Wondering if it is a leather?

 

[kingfisher62]

I am guessing some sort of macro algae!

 

[cooper13]

Cool. That was the other possibility I'd been looking at.