Can someone ID this white/clear slime on my live rock?

[littlenoodle]

Hi, I have 2 patches of this whitish clear slime growing on some of my live rock. It is slowly spreading. Does someone know what this stuff is? Thanks.

 

[davewbush]

Looks like sponges.

 

[aquasport24]

+1...they're harmless.

 

[LiveRound69]

yea looks like sponges to me as well