Veil

You create an veil of magic that passes in a line up to 40 feet long and 20 feet high. Creatures on your side of the veil and see through it normally, those on the otherside see a still image, of the casters choice - this could be an image of the terrain behind the line without showing the caster, an image of darkness, etc, however the image produces no sound and does not move.

Any creature may pass through the veil without penalty.