3-level Evocation
You evoke a fist-sized sized orb of fire in the air at a point within range. When a creature moves within 10 feet of it or begins its turn within that distance, the orb explodes: All creatures within 10 feet of the orb must make a Dexterity saving throw, taking 6d6 fire damage on a failed save, or half as much on a success. The orb's explosion spreads around corners.
If the spell ends or is dispelled before the ball detonates, it instead harmlessly vanishes.
When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot above 3rd.