Delayed Flame Burst

You mark a creature with elemental fire for future detonation. Make a ranged spell attack against a creature within range, on a hit the creature takes 1d8 fire damage and is shrouded in elemental fire. On the start of your next turn the shroud bursts into flame, the creature marked by the shroud and every creature within 10ft of it must make a Dexterity Saving Throw against your Spell Save DC, taking 3d6 fire damage on a failure and half as much on a successful save.

At Higher Levels: When you cast this spell using a 3rd level slot or higher the initial attack does an additional 1d8 damage for each slot level above 2nd. Additionally, the damage of the burst increases by 1d6 for every two slot levels above 2nd.