Imagine you were s two dimensional creature in a two dimensional plane. Width and length only, no concept of height. Let's say your world is like a piece of paper. Then, one day, a three dimensional create, 6 year old Thomas from Swindon, pushes s pencil through your piece of paper, your world. You have no concept of up or down. All you can discern is some disturbance in your field. Wouldn't that be spooky!