The Mace of Disruption is just about the most effective weapon against undead ever constructed (this item has appeared in every version of D&D, and in several computer games).
This mace appears to be a normal mace of high quality. It doesn't show its true power until it is used against the undead.
The mere touch of this mace will completely vaporize most undead creatures. Even vampires and mummies are affected most of the time. The mace actually severs their tie with the lowers planes (which is what keeps undead animated in the first place). Undead creatures of extreme power, such as Liches and Death Knights are rarely slain in one hit, but even then the weapon does double damage against them.
This mace is an item of powerful good, any evil creature attempting to wield it will be electrocuted with enough force to more than kill a normal man. This mace is exceedingly difficult to produce, and not more than a handful of them were ever made.
This is only my interpretation of this item, which is based largely upon its use in the older versions of the Dungeons & Dragons series of games. Your Mace of Disruption may vary, so always read the instructions.