What Is This Black Stuff On My Coral?

[reeftankdude]

Thinking about breaking that part of the coral off. Saw this before on the bone of one of my torches. A nerite snail consumed all of it off the tourch. However, will not eat it off this monti. Thnaks all

 

[Timfish]

My guess is some type of cyano. I'd try some airline to siphon it off.