Aerar's Exploding Javelin

You touch a nonmagical javelin. Until the spell ends, that weapon becomes a magic weapon Imbued with fire energy. When you hit with a ranged attack using this javelin it deals 1d6 fire damage plus strength mod to the target then transforms into a ball of fire, forming a 10ft. radius sphere centered on that target. Each creature in the sphere must make a Dexterity saving throw. A creature takes 4d6 fire damage on a failed save, or half as much damage on a successful one.

Flammable objects in the area that aren’t being worn or carried start burning. When the spell ends the javelin turns to ash.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, you may imbue an additional javelin for each slot level above 2nd.