Guildmaster's Guide to Ravnica
Wondrous Item The mortar has 4 charges for the following properties.
It regains 1d4 expended charges daily at dawn.
Molten Spray. You can expend 1 charge as an action
to loose a 30-foot cone of molten mizzium. Each creature in the area must make a DC 15 Dexterity saving throw, taking 5d4 fire damage on a failed save, or half as much damage on a successful one.
Mizzium Bombard. You can expend 3 charges as
an action to launch a hail of molten projectiles in a
20-foot-radius. 40-foot-high cylinder centered on a point
you can see within 60 feet of you. Each creature in the
area must make a DC l 5 Dexterity saving throw. A creature
takes 5d8 fire damage on a failed save, or half as
much damage on a successful one. Rare
This short tube, about 2 feet long and 6 inches in diameter, is made from mizzium, a magically enhanced metal alloy forged by the Izzet League . The end that's pointed toward a target is open, and a glowing ball of molten metal can be seen at the other end as long as the mortar has at least 1 charge remaining.