As an action, you can throw this magical device onto a surface you can see within 60 feet. Upon impact, the incense ignites, billowing out in a pungent, 15-foot-radius sphere, carrying with it the dragon’s toxins. A creature that starts its turn in the area or enters the area for the first time on a turn must make the associated saving throw, suffering the associated effects on a failure. Creatures are affected even if they hold their breath or don't need to breathe.

The cloud lasts for 1 minute if the air is calm. A moderate wind (at least 10 miles per hour) disperses the cloud after 4 rounds. A strong wind (at least 20 miles per hour) disperses it after 1 round.

Once a grenade has been used, it can’t be used again until the following dawn, when it must be re-filled with 100 gp of good-quality incense as well as a specified value of diamond dust.

Brass, Sleep; Rare. A creature must succeed on a DC 15 Constitution saving throw or fall unconscious for the duration of the gas’ presence. A creature with 100 or more hit points is immune to this effect. This effect ends for a creature if the creature takes damage or someone uses an action to wake it. Diamond dust: 300 gp.

Bronze, Repulsion, Rare. A creature must succeed on a DC 15 Strength saving throw or be flung up to 60 feet from the centre of the sphere, landing prone and taking 2d6 bludgeoning damage. If a creature collides with another creature, both creatures take 2d6 bludgeoning damage. If a creature collides with a solid object, it takes 4d6 bludgeoning damage instead. Diamond dust: 400 gp.