Spiderweb-like sponge(?) hurting corals help!

[Caprica6]

I've had this thing in my tank for months now, I can't seem to get rid of it and no one seems to know what it is. When I scrape it off the glass or one of my corals, it's mucous-like. I own a 150 gallon saltwater tank and it's trying to grow onto my polyps and my corals and it's killing them.

The photos I have of the mass is difficult to get to as it's in the back of the tank against the wall so forgive the quality.

 

[Innovator]

Looks to be an invasive sponge or possibly hydroids. If sponge it can easily be pulled, scraped, and/or sucked out. If hydroids you can use kalkwasser to blanket the colonies.