This was a plugin script circa 2014 (inserted via yet another plugin, Gryphonheart Items ), that allowed players in World of Warcraft to trade actual drawn canvases with each other in game. Since plugins could not import their own resources (or I chose not to), the "charcoal" was layered smoke sprites from the WoW filesystem, likewise the gold dust was a tinted cloud sprite. The stored drawing was a giant array of coordinate and texture data, a sort of hybrid between a raster and vector approach, because there were no methods available via the plugin API to get actual image data, I could only record mouse movements. The end result was pretty novel, and some artists spent some quality time with it, doing portraits. Here's Tarhoof's portrait gallery.
The full gallery:
Later I went on to make a web version. The backend is glitchy but the frontend drawing functionality is intact.