Brakmarian Oil (5e Equipment)
From D&D Wiki
This murky solution of velvet hue is known by alchemists as a volatile formula that took the life of one William Brak upon its discovery. Those afflicted by brakmar's touch are unfortunate indeed. Brakmarian oil typically comes in barrels and can burn for up to an hour before it starts to cool.
Boom. After being exposed to oxygen, the oil in the barrel violently gurgles and explodes in a 10-foot radius sending black snakes of smoldering tar and oil in all directions. All creatures in the radius must make a DC 15 Dexterity saving throw to remain unaffected.
Burn. On a failure, a creature takes 2d8 fire damage and thereafter, at the start of their turn they take 2d8 fire damage. An afflicted creature must use their action twice to remove all the burning oil from their body. Otherwise, the oil burns for up to an hour.
Cost: 500 gp
Weight: 275 lb.