Slime ID? Thin slime around a frag

[JerryRigged]

So while I've done tanks for a while off/on, I've been very lucky and have not had too many odd things show up before. I'm trying to figure out what this smooth slime is. I found a similar picture on the web somewhere else and it had varying opinions on what it was and how to treat from 'it will go away on it's own' to 'it will destroy your tank if you do nothing'
I've not messed with it yet as I didn't want to disturb until I knew what I might be dealing with. It might have come with the frag as it seems to be around it and I don't see it anywhere else in the tank.

The lighting in the pictures makes it look light purple/pink, but under a white flashlight it's a more consistent light tan/brownish.

Underside

Wider view

 

[rayadog]

Hmm looks pretty… unassuming. I generally do my water changes exclusively with air line tubing, so if it were me, I’d prolly just suck it out while I’m already in there. But that’s likely a ptsd response.

 

[StartingATank]

I am unsure, but if I had to guess, I would say it is a type of sponge? Also I noticed there were some vermetid snails on the bottom of the rock, I would recommend cutting them off and then covering the area that is left with super glue, as they can cause corals to die