Bran Riveroak’s inferno

You choose up to three creatures you can see within range and make their cells burn internally. The target must make a constitution saving throw. On a failed save the target takes 8d6 fire damage and on a success the target takes half as much damage. On the start of each turn the target must repeat the saving throw. On a failed save it takes 4d6 fire damage and on a success half as much and the spell ends. If the target dies while the spell is still active it explodes and sends on a 15ft radius and the fire goes around objets and corners. Every creatures in the area of the blast must succeed on a dexterity saving throw or take 2d6 fire damage. If a target gets out of range during the spell it ends at the end of the next caster’s turn if the caster does not get back in range.

At higher levels: You can choose 1 more target per spell slot lvl higher than 5th lvl.