Pyrotronum

A parallax illusion uses six still frame slices of a moving picture back-lit behind a clear film with scrolling vertical black lines revealing only one frame of animation at a time to make a moving picture illusion.

The trick to getting the fluid, dynamic feel of real flames in an electric fireplace is surprisingly simple
Light from a light bulb, often an LED, bounces off of a rotisserie-style silver refractor with three-dimensional patterns that create the illusion of a random flicker of flame.

These two things need to be combined.

At random intervals. or at the push of a button a stallion might run through the coals of your fake fireplace or a dragon might fly though those flames or...

...well you get it.

Expecto Pyrotronum!!!