It’s an undead baby dragon, produced by a failed magical spell. It probably would be cute if it weren’t partially decayed.

Young dragons are relatively defenseless. They are born with relatively soft scales, which are shed and replaced with harder ones as the hatchling matures. Once a hatchling’s wings grow in, it typically marks the beginning of maturation. At this point they are often capable of hunting on their own and are usually left alone by their mother.

Dandy doesn't seem to notice anything wrong with himself, though he does notice there is only one other dragon like him on Kanaye's scroll. He follows Athena Sparkle around and laughs gleefully when she grumbles and roars, as if it were all a show for him. When they are alone, which is often, Athena Sparkle mopes around, having no one to roar at. Dandy romps around, batting her tail and nipping at her nose, trying to cheer her up. Instead he makes her jealous of those happy times she knew she once had and it only serves to depress her more.