WHat is this growing on my rock

[BCReefer]

I have this thing growing on my rock. It looks like it has a clear/white sack with what looks like a brown with white underside. This is from some new rock that I put in 2 weeks ago. I have just started my tank 2 weeks ago so it is still going through its cycle.

CAn anybody tell me if this good or bad thing.

Many thanks.

 

[Anonymous]

Moving to Hitchiker Forum for identification insights.

[ August 25, 2001: Message edited by: galleon ]