What's growing in my tank?

[kjmsmith]

Hello, this is my first post and new to the hobby for 2 years and appreciate the great advice on this forum and all I have learned from it. I recently upgraded from a 55g to a 90g and during the move had an opportunity to inspect the live rock for any unwanted creatures. I didn't find anything too concerning but I did take a closer look at a piece of rock that had some anthelia on it that had been dying off. It was being replaced by a rubbery mass which I originally thought was the base of the coral. After reading up I haven't been able to identify what this actually is. I have attached a pic for anyone who may be able to identify it for me. It seems to be spreading and getting thicker. My water parameters are all within range. Other inhabitants include 2 ocellaris, 6 line wrasse, yellow tail damsel, bubble tip anemone, emerald crabs, pep shrimp, turbo snails. Other corals include green star polyp, kenya, Euphella, mushroom and toad stool. Lighting is reef LED's.
Thanks in advance for any assistance.

[cloak]

It's most likely just a sponge of some sort. (harmless)

Keep an eye on it though. Some sponges can be kind of invasive at times.

[spit.fire]

I agree on the sponge