Paint it, Wallpaper, Use faux Brick, Clad, Panel, Stencil, Paint effect, Add a Mirror,
Hang a picture, Tile, etc. etc............
Do you have a photo? That would help for ideas. :)
Anything you want.
Make sure you know exactly where the gas line runs before you drill or cut anything.
Yes, you know the heat convection currents go mostly upward from the fire box.