Corrupting flames

You conjure the vitality sapping flames of Phlegethos in a 10-foot-radius sphere originating from a point you can see within range. Each creature in the sphere must make a Constitution saving throw. On a failure, a creature takes 4d6 fire damage, and is poisoned. On a success, a creature takes half as much damage, and is not poisoned. A creature you can see regains an amount of hit points equal to the damage one creature of your choice took from this spell.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d6 for each slot level above 2nd.