Divine Smite

Level 1 Evocation (Paladin)
Casting Time: Bonus Action, which you take immediately after hitting a target with a Melee weapon or an Unarmed Strike Range: Self
Components: V
Duration: Instantaneous

The target takes an extra 2d8 Radiant damage from the attack. The damage increases by 1d8 if the target is a Fiend or an Undead.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 1.