Definition from the Dor Un Avathar X
Weapons that are considered a physical part of a monster. Used to simulate claws, horns, and so on. They cannot be affected by Magic or Abilities that specifically affect weapons (Pyrotechnics, Heat Weapon, etc.). Effects that normally treat weapons differently (Arrows, Fireball, Lightning Bolt, Sphere of Annihilation) that strike a Natural Weapon are treated as having hit the Monster in the arm.. Touch effects may be extended through Natural weapons (both ways) if declared within one second of contact. A player using a touch effect on a Monster’s Natural Weapon is only damaged, wounded, or killed if contact was made as a result of a melee attack made by the monster. Immunities and protections of a Monster extend to any Natural Weapons.