Been experimenting with filter animations, lately with wavy reflections.
The distortion is very simple, use a fractal noise for a displacement map. For the animation, add a hue rotate filter on top of the fractal noise.
Set the displacement map using the reds for x, and alpha for y. Because of the latter, make sure the source has 50% opacity everywhere.
In a nutshell.
Too bad this blog doesn't allow to embed svg-s (which is the main reason why I'm not up to thate with this recent work), so definitely check the svg source below.