Copper colored thing killing my coral

[mmurphy]

Please help me! I have this copper color thing growing on my rock. It started on the sand leaving spots that look like rust and white tubular structures. Continued growing upwards and now my coral looks terrible.
What is this? Thank you!

 

[Mr. Mojo Rising]

Kind of looks like hydroids. Are the individuals or one mass? If you touch it do they recede into a tube?

 

[Oldreefer44]

Possibly a sponge. Regardless, will require physical removal unless you like ie more than your coral.