Ember Seed (5e Equipment)
From D&D Wiki
Wondrous item, common
One of these rare, bright orange seeds is imbued with incinerate chemicals that ignite when pierced or smashed. This makes them them dangerous, magical ammunition when used in a blowgun, sling, slingshot, or seed shooter. When using a ember seed as ammunition, the attack inflicts fire damage instead of bludgeoning damage. The hit target must succeed on a DC 12 Dexterity saving throw or be ignited. Any creature with resistance or immunity to fire damage automatically succeeds on this save. An ignited creature takes 1d6 fire damage at the end of each of its turns, but it can use its action to end this condition.
An ember seed is destroyed after it hits a creature.