These are two bubble frags started 1 1/2 years ago and both were 50 cent piece size. The one nearest the cleaner wrasse kept getting knocked down by a pencil urchin so I stuck it down into the substrate about 7 months ago.
This picture shows me holding the original frag piece, and the projection of bubble flesh which had spread across the top of the aragonite substrate.
This picture shows the aragonite substrate bottom that the bubble grew over. This bubble frag is about 1" dia larger than the bubble frag that didn't get stuck down in the substrate 7 months ago.