BRIGHT orange growth

[duc]

I have had one spot on another rock for as long as I can remember, seems to come and go in the exact same spot. This morning we noticed this new spot and were able to get a pic of it.
It looks a lot brighter in person and is definitely orange.
Clif

[tgray]

Boring sponge?

[hobogato]

sponge??

[tgray]

some sponges secrete acid to bore thier way through limestone rock.

[duc]

The purple you see in the pic isn't a rock it is the skin of the coral in the pic.
Do sponges attach to coral?
The other spots I mentioned are on the rock itself but have never grown and are there then are gone, almost like an water condition growth not a life form.
Clif

[tgray]

they can compete for space with any attached organism and will weaken coral skeltons by dissolving the limestone.

[gjuarez]

Could be a sponge, but it could also be a different type of coraline. My rock once turned that color, completely. Both of the times were because of bad situations though. The first time it happened it was because I took the live rock to my house from my apartment and it probably had some die off from the transfer. The other time was when i came home to find out that the house temperature was 103 inside. All of my corals died and all my purple coraline became bright orange like the one on yours. I have tried to get the same color but its impossible to get. It might also be a sponge too.