Spike Growth

Wherever any type of plant growth of moderate size or density is found, this spell can be used. The ground-covering vegetation or roots and rootlets in the area becomes very hard and sharply pointed. In effect the ground cover, while appearing to be unchanged, acts as if the area were strewn with caltrops. In areas of bare ground or earthen pits, roots and rootlets act in the same way. For each 10 feet of movement through the area. the victim suffers 2d4 points of damage. He must also roll a saving throw vs. spell. If this saving throw is failed, the victim's movement rate is reduced by 1/3 from its current total (but a creature's movement rate can never be less than 1). This penalty lasts for 24 hours, after which the character's normal movement rate is regained.
Without the use of a spell such as true seeing, similar magical aids, or some other special means of detection (such as detect traps or Detect Snares & Pits), an area affected by spike growth is absolutely undetectable as such until a victim enters the area and suffers damage. Even then, the creature cannot determine the extent of the perilous area unless some means of magical detection is used.

Sphere: Plant
(Alteration, Enchantment)
Level: 3

Range: 60 yards
Components: V, S, M
Duration: 3d4 turns + 1/level
Casting Time: 6
Area of Effect: 10-foot square/level
Saving Throw: None

Material Components:
the priest's holy symbol and either seven sharp thorns or seven small twigs, each sharpened to a point