A stunned character or creature is unable to perform most actions, including movement and speech, and receives a -20 penalty to their defensive strength and 50 percent penalty to their evade/parry/block chances. The only roleplaying verbs available to a stunned character are SWAY and WHEEZE; however, SWAY is unavailable to a character that is not standing.
Stuns are typically measured in "rounds", where each round is 5 seconds.
Stuns do not stack and cannot be reapplied before the full duration has elapsed. If someone is stunned for two rounds and is then hit with an attack that would normally stun for six rounds, they will still only be stunned for the initial two round duration.
Each entry in a critical table has an associated stun period, and a character or creature who is hit by any standard attack will be stunned for the listed number of rounds. Many combat maneuvers and creature maneuvers cause victims to be stunned if they fail a defensive roll. Some spells can directly cause stuns without any critical damage, including but not limited to: Blind (311), Censure (316), Hand of Tonis (505), Mind Jolt (706), and Stunning Shout (1008). Certain spell failures can cause the caster to be stunned, including but not limited to failure of: Living Spell (208).
A wide variety of creatures are immune to stuns (including any elite creatures for tasks assigned by the Adventurer's Guild and the Guardians of Sunfist, even if the base creature type is normally susceptible), and others are able to shake off a stun when they take their next action.
Additionally, some professions can gain access to special verbs and abilities to aid them while stunned:
- The BESEECH verb is available to Paladins through Divine Intervention (1635).
- STUNMAN is available to Rogues through the Rogue's Guild. Warriors and Monks can also learn this verb by training in Combat Maneuvers.
- Warriors can BERSERK while stunned in effort to break a stun.
- Empaths (and anyone joined) that have Troll's Blood (1125) active have a chance to break non-magical stuns.
- Bards can break stuns on either their group or themselves with Troubadour's Rally (1040).