This is a simple rule that can be added to any role-playing game that utilizes armor class in combat resolution.
Any attacker who uses an appropriate weapon with the intent of pulling, pushing, toppling, entangling, or unhorsing an opponent may consider that opponent to be unarmored in terms of armor class regardless of whatever armor that opponent may be wearing. If the opponent is aware of the attack and able to react, the opponent's armor class will be modified by his or her Dexterity bonus or penalty, if any. Appropriate weapons include whips, bolas, man-catchers, and most pole arms (namely those with hooks and/or tines). If the attack is successful, it causes no damage, but the victim is affected as follows:
- whip: entangled (potentially tripped or disarmed)
- bola: entangled (potentially tripped)
- man-catcher: caught (potentially pushed or pulled)
- pole arm: unhorsed or tripped
Effects may be adjudicated by GM fiat, GM-player negotiation, attribute checks, or any extant rules covered by the system being used.