weird sponge i think

[elke]

dont know if or if it isn't a sponge please help pics attached its yellow kinda looks like puke on a rock but fuzzy...lol any ideas if good or bad please tell.....it has engulfed the whole peice of rock now which is about a 5lbs peice of rock and growing bigger and starting to get thicker please help

 

[Fluff]

How old is your tank? One pics it looks like it may be die off, the last pic makes it look like it may be the start of some hair algae.

 

[elke]

my tank is about 9 months and it is not hair alage went threw that my cleaner shrimp which you can see him slighty in the back of the one pic lives and goes nowhere else in the taank if you scrape it of it feels spongy it is yellow in color and about a half inch thaick now sorry for the pics its the best i could focus on it