The ugly side of reefing

[cyclejockey]

So this showed up a few weeks ago. It keeps getting bigger and bigger. I'm not home to address it right now but I'll be removing it when I get home, this week. Any ideas? It started on the glass around my gsp. Then, it started growing ON the gsp. The second pic is what the coral and glass looked like a month ago.

 

[carmodpg]

Tough to see without the lights on. Is it some sort of sponge?

 

[cyclejockey]

I'll have to get to messing with it when I get home. I'll post another picture and a better description when I start playing with it.