Spike Stones

Rocky ground, stone floors, and similar surfaces shape themselves into long, sharp points that blend into the background.   Spike stones impede progress through an area and deal damage. Any creature moving on foot into or through the spell’s area moves at half speed.   In addition, each creature moving through the area takes 1d8 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 on a Reflex save to avoid injuries to its feet and legs. A failed save causes the creature’s speed to be reduced to half normal for 24 hours or until the injured creature receives a cure spell (which also restores lost hit points). Another character can remove the penalty by taking 10 minutes to dress the injuries and succeeding on a Heal check against the spell’s save DC.   Spike stones is a magic trap that can’t be disabled with the Disable Device skill.   Note: Magic traps such as spike stones are hard to detect. A rogue (only) can use the Search skill to find spike stones. The DC is 25 + spell level, or DC 29 for spike stones.
 

Rocky ground, stone floors, and similar surfaces shape themselves into long, sharp points that blend into the background. Choose four 10-foot Squares of solid stone surface in range to be affected. Each Square must touch at least one other on one or more sides.   Spike stones impede progress through an area and deal damage. Any creature moving on foot into or through the spell's area moves at half speed. In addition, each creature moving through the area takes 1d8 Piercing damage for each 5 feet moved through the spiked area.   Any creature that takes damage from this spell must also succeed on a Dexterity saving throw to avoid injuries to its feet and legs. A failed save causes the creature's speed to be reduced to half normal for 24 hours or until the injured creature receives magical healing. Another creature can remove the penalty by using 10 minutes and succeeding on a Wisdom (Medicine) check against your Spell Save DC.   Spike stones are incredibly difficult to spot, and can only be found with a Wisdom (Perception) check with a DC equal to 5 + your Spell Save DC.   At Higher Levels. When you cast this spell using a higher level spell slot, increase the number of 10-foot Squares affected by this spell by 1 for each slot level above its base level.