It's possible it's a 'shiny'. I met someone who had a Musharna with uncommon coloration, and apparently it's perfectly healthy and has no difference beyond the color, but there isn't much documented information about them. Could you give me an image of it?

[By now, he's realized that she doesn't like video, which he totally gets because he doesn't like it either. Yet it would be easier to tell if the Haunter is a shiny or something else if he could actually get a look at it.]