Crushing Clockwork

You summon spectral clockwork gears that begin to churn and crush a creature of your choice within range, forcing it to make a Strength saving throw. On a failed save, a creature takes 4d8 bludgeoning damage. On a successful save, a creature takes half damage and suffers no other effects. A creature that failed its save against the spell takes another 2d8 bludgeoning damage at the beginning of each of its turns for the spell’s duration, and can reroll its saving throw at the end of each of its turns, ending the spell on a success.