Electrify

You channel lightning into your hands. The next time you hit a creature with a melee attack (including a melee spell attack) before the start of your next turn, the target takes 1d12 lightning damage and must make a constitution saving throw. On a failed save, the target becomes stunned until the start of their next turn.

The spell ends after dealing damage, or at the start of your next turn, whichever occurs first.