Move the mouse around and Scratch Cat will follow. If you it moves fast then you will see my attempt at simulating motion blur in Scratch.
The scripts automatically detect how much movement the sprite has made and use ghosted clones to create the effect. It works OK but not great. The clones would be better closer to the sprite. It may work better to use one clone that stamps but that would interfere with other stamping. I was trying to make the script independent and easy to drop into any project.