Hellish Rebuke

Casting Time: 1 reaction, in response to being damaged by a creature you can see Range: 60 ft.
Components: V,S Duration: Instantaneous
You point your finger and that creature is momentarily surrounded by hellish flames. The creature must make a dexterity saving throw. It takes 3d10 fire dmg on a fail, or half on a success.
Tiefling Ability. Cast it once per day as a 2nd level spell.