Crippling Agony - Kibble's Tasty

You can inflict crippling agony on a foe. Choose one creature that you can see within range to make a Constitution saving throw. If the target fails, it becomes crippled with
horrific pain. Whenever the creation moves more than half of it's movement speed or takes an action, the crippling pain causes it to take 1d6 necrotic damage. It can repeat the saving throw at the end of each of its turns, the target can make a Constitution saving throw. On a success, the spell ends.