Derik's spontaneous combustion

You point your finger at a non-living object within 60 feet worth less than 10gp that is not being worn or carried and it explodes. Every creature within 20 feet of the object selected must succeed a Dexterity saving throw or take 3d6 damage (the damage type depends on the object selected if it is wooden it will deal piercing due to shrapnel), they take half damage on a successful save. If the object is larger than 5 feet, every part of the object within 5 feet of the spot you pointed at will explode instead of the entire object.