mantra,
Waldo is partially correct here. Burning in pixels is a function of the contrast and shading which exists between areas of the screen and the pixels within them......light against dark to make it simple.
Since the Avast screen saver is "light against dark"...it was better to make it move.
However, I have many great "static" screensavers that do not move but have low contrast and gentle shading between areas on the screen. Bright crisp screensaver can and most likely will...burn in a pixel or two!
Enjoy Avast!