Elemental Bane

Casting Time: 1 action
Range: 90 feet
Duration: Concentration, up to 1 minute
Choose one creature you can see within range,
and choose an elemental damage type. The
target must succeed on a Constitution saving
throw or be affected by the spell for its
duration. The first time each turn the affected
target takes damage of the chosen type, the
target takes an extra 2d6 damage of that type.
See XGE, pg. 155.