This sticky, adhesive fluid ignites when exposed to air. This large glass sits in a wired cage. The glass lid is wired shut with a small metal latches to keep the lid in place.
As an action, you can undo the latches and throw the jar up to 20 feet. Upon impact the lid is knocked loose which causes the vacuum in the jar to fill with air and explode. Make a ranged attack against a creature or object, treating the alchemist's fire as an improvised weapon. On a hit, any creature within 10ft of the impact point takes 2d10 fire damage and then 1d6 fire damage at the start of each of its turns. A creature can end this damage by using its action to make a DC 10 Dexterity check to extinguish the flames.
On a fail, the pressure inside the jar was too much and did not loosen the lid enough to trigger the explosion. Unless the lid is latched once more, roll a d20 at the start of every turn to see if it goes off.