Razor Rock

Razor rock underfoot is a menace to movement. PCs treading on razor rock must reduce their movement rate to one-quarter normal to be sure of not incurring risks. Walking any faster forces a PC to make a Dexterity check. If this is failed, the PC's feet suffer d8 points of damage from the abrasive, jagged rock for each 20 feet traveled. Running is highly dangerous, imposing a +4 penalty to the Dexterity check and increasing damage suffered to d8+3 hp. Falling or being knocked down results in d8+3 points of damage. Armor reduces 1 point of damage for every 3 points of Armor Class above AC 10 (-1 point at AC 7, -2 points at AC 4, -3 points at AC 1, and so forth).

If the character suffers a total of 10 or more points of damage to the feet, he or she must make a Constitution check at a +4 penalty to ignore the pain; failure means the agony is such that the PC cannot move further and must stop and bind his or her damaged feet. A character who ignores the pain and continues on, accumulating a total of 20 or more points of damage to the feet, does permanent damage and cannot walk until he or she receives Cure Critical Wounds, Heal, or Regenerate. Only stationary, self-defensive combat actions are possible to a character immobilized from foot damage. Spellcasting is possible, but only on a successful Constitution check.

Note that mounts (mules. etc.), having more sense than the average adventurer, will absolutely refuse traverse razor rock.