Don't know what this is? Is it good or bad

[frank323]

This thing has been rapidly growing from my yellow polyps. I tried to take a picture of it but still learning how to shoot through glass.
Anyways I think it might be a hydropod of some type.
this thing grew to about 2 inches in less than 2 weeks.
Should I try to remove it. Pretty new to hobby so any help would be greatly appreciated.

 

[leigh]

that growth rate would sure scare me!
see what bang guy has to say...he's a bug guru of sorts

 

[frank323]

Thought i would try to enclose a better picture.
I think I need a better digital camera
I also notice there is another one growing on a different part of the polyp.

 

[bang guy]

It looks like some sort of Sponge to me. Can you describe it in detail? or... e-mail an uncompressed picure to me to look at.