Asmodeus' Jar

This round, clay jar is about as big as a medium sized cannon ball and looks very old. It has a compression stopper in its mouth and reeks of sulphur and phosphorous. As an action, a character can prime this highly explosive device by pressing in the stopper and throw it at a point up to 60 feet away. Each creature in a 15-foot-radius sphere centered on that point must succeed on a DC 14 Dexterity saving throw or take 3D6 force damage plus 5D6 fire damage and catch fire. Damage is halved for a successful save and the creature is not on fire. For each subsequent turn any creatures on fire make an additional DC14 saving throw to extinguish the fire or take an additional 1d6 fire damage per turn.

Notes: Damage