Walking Bomb

You infuse the blood of your target within range with a corrosive explosive. The round you cast this spell, the target must make a constitution saving throw against your spell save DC. On a failure, the target takes 1d6 + Modifier Damage. At the end of each of the target's turns, they can reroll the saving throw. On a success, the spell ends. 

If the target continues to fail their saving throw, the take 1d6 more damage at the end of each of their turns. If the target dies while under the effect of this spell, they explode in a spray of blood, flesh, and bones. Anyone within 10 ft. of the exploding victim takes 2d6 damage.