The Starburst axolotl is just that! It looks like a galaxy! Starbursts characteristically have largely formed clusters of iridophores (flakes of gold) on their heads and body. These clusters tend to increase in number and size as the specimen ages.
Just like all the other morphs, each one is an individual and may have different levels of clusters. Higher grade specimens have a very large amount of clustering and typically cost more. Awesomeness!