NAPALM

NAPALM is a Windows utility that enables you to draw over your desktop by using an animated fire ink.

Once you finish working on your drawing, you can then save it to your local directories.
The application is packed with a wide variety of drawing settings, provides you with multiple theme samples, and offers you detailed instructions. You can adjust the saturation and hue levels of the flames, choose the preferred thickness and FPS values, and so much more. Once you finish your drawing, you can export it to your local folders. Another cool thing about this utility is that it offers you an option which can be applied to your desktop icons to make them look like they're on fire.

This program also enables you to define various hotkeys for immediately completing various types of tasks (for example, to reveal the Settings window).

The only thing that bothers me is the fact that it uses a significant amount of CPU resources while operating in front (more than 20%).

Still, this program comes without a price. So, if you're looking for a fun way to customize the appearance of your desktop, NAPALM might be the application for you.