When cast, a small burst of fire appears at a point you choose within range that swirls around whilst priming itself for detonation. A 10-foot sphere blast radius around the point is visually indicated with a harmless ephemeral aura. At the beginning of your next turn, the fire momentarily vanishes before blossoming into a 10 foot radius explosion of flames, inflicting fire damage equal to 4d12 + your spellcasting modifier to every creature caught in the blast that fails a Dexterity saving throw, or half as much damage on a successful one. Both the aura and the fire spread around corners. The fire ignites flammable objects in the area that aren't being worn or carried.