Alchemist's Fire

This sticky, adhesive fluid ignites when exposed
to air. As an action, you can throw this flask up
to 20 feet, shattering it on impact. Make a ranged attack against a creature or object, treating the alchemist's fire as an improvised weapon. On a hit, the target takes 1d4 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.