The humble cotton bud, when teased out a little, and rolled in pva glue, and painted looks a little like a torrent of flame erupting from some poor, unsuspecting super heavy vehicle.
I based mine on a little plastic circle I picked up from somewhere. I left a bit of the plastic rod inside, and glued it to the base. Then teased it out a little, and painted it up. I was hoping to make them bigger and more imposing looking, but I might do that down the track by adding some clump foliage to it and painting it a nice smoky grey, with red underneath for a dramatic glow effect.
But for now they will do. I have a game tonight with a few super heavies in it, so will try them out.