Crippling Shot

When you hit a creature with a ranged weapon attack that qualifies for Sneak Attack, you can attempt to hinder its movement.
The target must succeed on a Dexterity saving throw or have its speed reduced to 0 until the start of your next turn.

The saving throw DC equals:
8 + your proficiency bonus + your Dexterity modifier

You can use this feature a number of times equal to your proficiency bonus per long rest.