I think it's a peanut worm?

[stanleo]

This is in a GSP colony. It waves with the current and I can only see it at night or early morning before the GSP fully opens.

Also the white mass next to it. It started out small and was only visible when the GSP wasn't open. When it was small I noticed a siphon so I thought it was a sponge. Is that what it is? It has grown to four times the size now and it does feel spongy but I can't get it off easily.

 

[WV Reefer]

This is in a GSP colony. It waves with the current and I can only see it at night or early morning before the GSP fully opens.

Also the white mass next to it. It started out small and was only visible when the GSP wasn't open. When it was small I noticed a siphon so I thought it was a sponge. Is that what it is? It has grown to four times the size now and it does feel spongy but I can't get it off easily.

hard to tell from those pics.

A peanut worm will move it’s body similar to an elephant trunk feeling around for things to grab.

the white thing does look like a sponge and if you are seeing siphons it probably is a sponge of some sort. Some are more aggressive than others so if it’s bothering things just tweeze it off the coral.