Alchemists 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 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, increasing the DC by 1 for each rarity beyond common. 

Instability. As the concentration and effectiveness of this highly combustable material increases, so does the risk. Common Alchemists Fire has an Instability rating of 10% increasing by a further 10% for each level in rarity. When a creature would throw Alchemists fire, roll a d100. If the result is higher than the Instability Rating, the attack continues as normal. Otherwise, the fluid combusts igniting the wielder. 

Notes: Damage, Consumable