Take the image below for example:
For the shadow to travel from point A to B would be extremly fast on the surface on the moon but probably not breaking the speed of light. But if the moon were 20 times larger then it would appear that the shadow would be travelling 20 times faster appearing to break the speed of light on the surface of the moon.
So in essence the bigger an object is the quicker that shadow would appear to move on the surface of that object.
So what does this mean in terms of breaking the speed of light?
Also for interesting purposes, what is the speed of dark (if it even has a speed?)