While shouting "magic missile", you throw an oil flask at one creature within range. Make a Dexterity(Firearms or Improvised weapons) check contested by the target's Dexterity(Acrobatics) check.   If you succeed, a rainbow fire with a 5-foot radius is created on that creature's tile.
If you fail, the same rainbow fire is created behind them. How far is determined by the DM.   The fire lasts for 3 turns. Any creature that comes to a stop in the fire for the first time on a round or starts its turn there, takes 5 fire damage.   This spell is not affected by anti-magic effects such as counterspell or Antimagic Field.