Thermovariance

You point to one creature you can see within range, and shout an incantation to the Nine Hells. The ground underneath your target suddenly warms. The target must succeed on a Constitution saving throw or take 3d10 fire damage as its blood begins to boil inside its veins. If the creature is wounded or missing any of its hit points, it takes 1d6 more fire damage. 

When you cast this spell using a spell slot of 5th or higher, you may choose up to three targets total for this spell.