Skullcrusher

Skullcrusher is an enchanted mace +3. It inflicts 1d6 +4 points of crushing damage and 2 extra damage against humanoids. It has -3 THACO bonus, weighs 6 lbs and it has a speed factor of 4. This item appears in Baldur's Gate II: Shadows of Amn and Baldur's Gate II: Enhanced Edition. It's not known where it can be found.

In-game description
"Mace +3: Skullcrusher This mace is permanently bloodstained; a telltale trace of its many years spent bashing heads. The weapon would have been the bane of humanoids throughout its history, but those that wielded it seem to have been purposely left out of historic record."