Creeping Shadow

You point a finger at a creature, and their own shadow briefly turns hostile, clawing at their ankles. The target must succeed on a Strength saving throw or take 1d6 necrotic damage and have its speed reduced by 5 feet until the start of your next turn.

Persistence: If the target is in dim light or darkness when they fail the save, they take an additional $1d6$ necrotic damage at the start of their next turn as the shadow refuses to settle.