So lets say the unmovable object is a gas giant that never listens to anyone and the unstoppable object is light, because light is considered matter and an object, moving at a constant speed, and it causes the gas giant to glow a tiny bit at the edges, but the light passes through the clouds, as they are not that thick, because it is of similar clouds and wind speeds to that of neptune, and the unmovable object stays unmoved, and the unstoppable one is still going strong.