It's like a black pattern on the belly. It looks cool and will make your dragon look scary. That is one of Beardie's way on communicating.
Bill, my juvie loves to snuggle, and demands attention all the time. This morning I woke up late, and when I turned on her light, I saw her so black and patterned. I picked her up and put her on my chest, within 5 minutes she seemed relaxed and all white.