"It was truly a sight to behold. The biggest, ugliest half orcs I'd ever seen drew their blades and cornered Rathgar. They just laughed when he pointed his mug of ale at them. They weren't laughing moments later he soundly thrashed them with it, though. He didn't spill a drop either. I may need to procure one of those fancy drinking steins. Dwarves... they know how to fight and they know their booze."
Simple Melee Weapon
Name Cost Damage Weight
War Mug 20 GP 1d4 Bludgeoning 1 lb. (empty)
Though it looks plain, the Diplomat's Friend is actually a +1 war mug. The original mugs were given to dwarven emissaries as gifts to foreign VIP's. When the command word (the dwarven word for thirst) is spoken the contents of the mug are turned into dwarven ale. This ale must be imbibed immediately or the liquid with transform back into its original state.
Weapon, very rare (requires attunement)
This +2 war mug was enchanted for a human barbarian by his avariel bladesinger adventuring companion. Crafted from stone blessed by clerics of Moradin (the barbarian's patron). While attuned to this weapon the owner gains the benefits of the Tavern Brawler feat and none of the disadvantages from being drunk. In addition an enchantment prevents beverages from ever spilling from the mug, even when it is used as a weapon.
These +1 war mugs are made of the finest metals and gems. Despite their construction beverages in the stein always taste excellent. Beverages (including potions) in the stein can be imbibed as a free action once per round. The steins have secure lids, to prevent spillage. Unlike normal war mugs, battle steins do 1d6 bludgeoning damage.
This is a revision of a post I made right after 5E came out. I feel like I have a better grasp on the rules now.