Hallucinatory Terrain

By means of this spell the magic-user causes an illusion which hides the actual terrain within the area of the spell's effect.

Thus, open fields or a road can be made to look as if a swamp or hill or crevasse or some other difficult or impassable terrain existed there. Also, a pond can be made to appear as a grassy meadow, a precipice look as if it were a gentle slope, or a rock-strewn gully made to look as if it were a wide and smooth road. 

The hallucinatory terrain persists until a dispel magic spell is cast upon the area or until it is contacted by an intelligent creature. 

Each level of experience of the magic-user enables him or her to affect a larger area. At 10th level, a magic-user can affect an area up to 10" x 10" square, while at 12th level the spell caster affects a 12" x 12" square area. 

The material components of this spell are a stone, a twig, and a bit of green plant — leaf or grass blade.