Alchemical Bomb

You rapidly assemble, prime and throw an alchemically catalysed explosive, targeting either a creature or and unoccupied space of your choice within range. If targeting a creature, make a ranged spell attack against the target. On a hit, the target takes 1d8 fire damage as the bomb explodes, and all creatures within 5 feet of the target take fire damage equal to your spellcasting ability modifier.

If you target an unoccupied space, all creatures within 5 feet of the space must make a Dexterity saving throw, or take fire damage equal to your spellcasting ability modifier, as though they were secondary targets of the bomb. 

The bomb's potency increases when you reach higher levels. At 5th level, the main target takes an extra 1d8 fire damage and the fire damage to the secondary targets increases to 1d8 + your spellcasting ability modifer. Both damage rolls increase by 1d8 at 11th level and again at 17th level.