Dark flame

You create a small dark flame and hurl it at an enemy you can see within range. They must make a decision saving throw or take 4d8 fire damage and be considered lit on fire. Every turn the enemy spends on fire they take 8 fire damage at the start of their turn. The only way to put it out is to surround yourself completely with water. 

If a creature gets within 5 ft of the target that is on fire or anyone set on fire from this spell, they must roll the save and on a fail are set on fire taking the damage as well. If an enemy tries to put their friend out willingly, they automatically fail the check. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.