Don't know, I want to know what it is before I go and touch it
I realize it can't hurt me too bad, but I don't know how delicate it is. I've touched a few things in by tank and broken them off. This is about the size of a quarter and has taken about a month to get that size. Don't think it's an animal, but what do I know

Does have a white dot in the center, but don't know if it's a grain of sand or what. I will try to aggitate it tonight and see if it responds.
What are the possibilities?