Flagellate

Conjuration cantrip
Casting time: 1 action
Range: 15 feet
Target: A creature you can see within range
Components: S
Duration: Instantaneous
Classes: Cleric
Subclasses:

You create a barbed whip that strikes out at a creature you can see within range. Make a melee spell attack against the target. On a hit, the creature takes 1d6 magical slashing damage. You may choose to gain one level of exhaustion34 to deal an additional 1d6 magical slashing damage with this attack.

At Higher Levels. The spell’s damage on a hit and when you gain a level of exhaustion in order to increase the damage of the attack both increase by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).