I have had my Nukes get the brown around the mouth after ruff handle.....I also think the coloring of the skirt can be determined by the type of lighting, I used to have my PDs get real dark purple and bright blue skirts. I never really seen anyone else get them they way I did......I would have to say Nuclear green under possible morphing or stress from fragging or something.....But then again I could be wrong as there is always that possibility....LOL