If you want to create fog at the floor, you have to use white satin or transparent foil. Paint the photo with small light beams and take care that you never touch the floor with it. If you are ready go back to the camera, turn the lens out of focus and now you can paint the floor with the light and the colour you choose.

The glitter powder makes wonderful effects if you paint with light and you can colour the hair with a red filter at a penlight...