Sand Trap

Tearing the map to tiny pieces that disappear with the wind, you put a curse on the sand in the area, providing a nasty surprise for those who would cross it.

You trap an area of sand. You must designate a 30–foot radius “trigger area” somewhere within the larger area. When a creature sets foot inside the trigger area, the trap is sprung, and all of the entrapped area is affected with one of the following effects (your choice):
 * Drum Sand Every footstep taken within the entrapped area of sand is amplified so loudly that it can be heard for miles, typically attracting predators.
 * Sand Spikes Treat the entire entrapped area as though affected by spike stones.
 * Slip Sand The entire area of sand becomes difficult to travel. Treat the area as if affected by the grease spell.