Constable's Nail

The material below is Open Game Content from a 3PP Source

Constable’s Nail: This bent iron nail is often given to young halflings to commemorate tasks involving capturing a criminal or another outlaw and bringing her safely to trial. A halfling who uses it while casting magic weapon may have the spell give the weapon the merciful ability instead of an enhancement bonus. In the hands of anyone but the caster, the weapon loses the merciful ability and reverts to the normal effect of magic weapon.