While many forms of undergrowth can slow explorers, thorny brambles can prove a serious impediment. In addition to functioning as light or heavy undergrowth, brambles damage creatures that move through a space filled with them. The amount of damage taken depends on whether the brambles are light or heavy and what type of armor the creature wears. Light brambles deal 1 point of damage to a creature wearing light armor that moves into their square, while heavy brambles deal 1d4 points of damage to a creature in light armor or 1 point of damage to a creature in medium armor. Creatures in heavy armor don’t take damage from brambles. A creature unwillingly forced into brambles can attempt a DC 15 Reflex save to avoid taking this damage.
Additionally, a creature moving through brambles must succeed at a Reflex save (DC 12 for light brambles, or DC 16 for heavy brambles) or become entangled. Entangled creatures can attempt to free themselves as a standard action with a successful Escape Artist or Strength check at the same DC. A creature needs to attempt this save against being entangled by brambles only when it enters a square of brambles.
A 5-foot square of brambles has AC 5 and hardness 2. A 5-foot square of light brambles has 30 hit points, while a 5-foot square of heavy brambles has 60 hit points. If a square of heavy brambles is reduced to 30 or fewer hit points, it functions as a square of light brambles instead.
Pathfinder Roleplaying Game: Ultimate Wilderness © 2017, Paizo Inc.; Authors: Alexander Augunas, John Bennett, Robert Brookes, John Compton, Dan Dillon, Steven T. Helt, Thurston Hillman, Eric Hindley, Mikko Kallio, Jason Keeley, Isabelle Lee, Jason Nelson, Stephen Radney-MacFarland, Alex Riggs, David N. Ross, David Schwartz, Mark Seifter, Jeffery Swank, and Linda Zayas-Palmer.