An airtight flask containing a flammable liquid, either a potion suffused with Flame energy (if a magic user can craft a potion and knows a fire spell) or a dragon’s spit.
It can be thrown, causing 1d6 flame damage on a direct hit, and 1 flame damage to all creatures within 5 feet of the target. In turns after that, the things hit will ignite if flammable and take 1d6 flame damage for every found ignited. This fire can spread.
Extinguishing the flames requires a reflex save that is DC 15 for cloth and 20 for flesh or oily substances.
Rolling will give a +2 on this roll and immersion in cold or water will extinguish the flames.
Sucessfully crafting this requires at least 20gp for the vial and a DC 13 check. More expensive vials give +1 for every additional 10gp.
Dragons use their craft skill, while mages/wizards/etc use their potion brewing skill.
On a success, the potion will last indefinitely.
On a mild failure (a roll of 10-12)the potion will become useless in a day
On a failure, the potion will not be effective and fail
On an extreme failure, the potion will detonate, dealing its damage to the brewer unless they succeed on a reflex save. The damage is 1d6 not fire damage followed by ignition.
On a critical success, the potion’s splash radius is increased to 10ft, and its damage is doubled