Spike Growth

Any ground-covering vegetation in the spell's area becomes very hard and sharply pointed without changing its appearance. In areas of bare earth, roots and rootlets act in the same way. Any creature moving on foot into or through the spell's area takes 1d4 points of piercing damage for each 5 feet of movement through the spiked area. Any creature that takes damage from this spell must also succeed at a Reflex save or suffer injuries to its feet and legs that slow its base speed by half. This speed penalty lasts for 1 minute.