Dwarven Battle Tankard (3.5e Equipment)
From D&D Wiki
The Battle Tankard was designed with the Dwarven bar patron in mind. Made of steel and stone was designed as both a fully functional personal tankard as well as a bludgeoning weapon, thus it does not incur the -4 penalty of an improvised weapon. Due to its size and weight, it is considered an exotic weapon. However, unlike most Dwarven weapons, there is no way for anyone but a Dwarf to treat this as a Martial Weapon.