Rot Foot

3rd-level necromancy
Casting time: 1 action
Range: 60 feet
Target: a creature you can see within range
Components: S, M (a handful of maggots)
Duration: Instantaneous
Classes: Warlock, Blood Hunter, Wizard
Subclasses: --

You attempt to cause a deep rot in the legs of a creature you can see. The target must make a Constitution saving throw. On a failed save, the target takes 1d4 necrotic damage for every 5 feet of movement it takes before the start of your next turn.