Bludgeoning is a physical damage type caused by smashing an opponent with a heavy, flat or rounded surface. This type of damage can be mitigated with bludgeoning damage immunity, bludgeoning damage resistance, or general damage reduction. It is often a favored damage type of undead hunters, as skeletal undead (e.g. skeletons) tend to have 50% immunity to other physical damage types, but not to bludgeoning damage.
Weapons that cause this type of damage include: club, flail, hammer, mace, dire mace, magic staff, morningstar, quarterstaff, sling, and unarmed strike. In addition, many creatures have creature weapons (slams) that cause bludgeoning damage.
The following spells cause bludgeoning damage: bombardment, ice storm, earthquake, Evard's black tentacles, and drown.
The standard items brawler's belt and greater brawler's belt provide bludgeoning damage resistance (5/- and 20/-, respectively).