The CFA Splitcase Scarface PMD is meant to immitate an emerging PMD Dun from its Nymphful shuck. The Nymph forms a gas bubble, helping it rise to the surface. It's on that journey when it starts to emerge towards the top and and out of it's shuck into an adult. It's at this point that it will reaveal it's true color; the bright PMD yellow on top of it's thorax.