This +2 dragonbane guisarme seems to vibrate with a low hum. On a successful hit, the target must succeed at a DC 20 Fortitude save or become staggered for 1 round. If the target is of the dragon type and the dragon fails its save, the creature is stunned for 1 round and staggered for 2 rounds thereafter. It is staggered for 1 round even on a successful save.
Pathfinder Player Companion: Dragonslayer’s Handbook © 2013, Paizo Publishing, LLC; Authors: Shaun Hocking, Marie Small, and Jerome Virnich.